With the gradual development of education and technology, the scientific literacy training of young people is not only related to the technological progress and democratic development of society, but also affects the survival and growth of students themselves. However, due to the complex influence of various social factors, there are still a large number of disadvantaged students in our country, and the development of their scientific literacy faces multiple risks such as shortage and poor quality of scientific education resources. This research aims to demonstrate the overall status of the scientific literacy of students from socioeconomically disadvantaged families in China, to identify the risk factors that affect the Chinese socioeconomically disadvantaged student from the overall ecological system of individual development, and to construct the cumulative contextual risk model of scientific literacy of Chinese socioeconomically disadvantaged students. Also we explore the protective effect of different individual protective factors, and whether the protective factors can be accumulated together to counter the risk factors.

The subjects of this research come from the four provinces (cities) of China (includes Beijing, Shanghai, Jiangsu and Guangdong )in PISA 2015, focusing on 2,433 socioeconomically disadvantaged students whose family economic status is in the bottom quarter of the region. The research is divided into three parts: Part 1 conducted descriptive statistics on the scientific literacy of students from socioeconomically disadvantaged and non-disadvantaged families in China, as well as students of different genders, and used independent sample t-tests to compare the differences in their scientific literacy levels; Part 2 selected risk factors which causes significant differences in scientific literacy, described the cumulative contextual risk index and distribution of Chinese socioeconomically disadvantaged students, and establish a multilevel regression model for scientific literacy by cumulative contextual risk factors; Part 3 used multilevel regression to analyze the main effects of protective factors and interaction between cumulative protective factors and contextual risk. The main conclusions are as follows:

1. The disadvantaged family economy has a significant impact on students' scientific literacy and scientific attitude. In the group of students from disadvantaged families, gender has a significant impact on the scientific literacy, but has no significant impact on scientific attitudes.

(1) The overall scientific literacy of non-family economically disadvantaged students and the scores in various abilities, knowledge, and thematic dimensions are significantly higher than those of economically disadvantaged students from families.

(2) Non-family economically disadvantaged students have higher scientific self-efficacy, stronger epistemological belief in scientific inquiry, and a higher awareness of environmental issues.

(3) Boys from disadvantaged families have higher scores on overall scientific literacy and various abilities, knowledge, and subject dimensions than girls, but both boys and girls have lower scores on scientific attitudes, which shows no significant difference.

(4) The students from disadvantaged families are mainly distributed in non-urban schools. Only when they study in rural or big cities at the same time, the scientific literacy of students with disadvantaged families is significantly lower than that of students with disadvantaged families.

2. Compared with students with good family economic situation, students with disadvantaged family economics face multiple contextual risks in their growth, which will reduce their scientific literacy level.

(1) In the school field, the shortage of educational materials, the shortage of teachers, creative extracurricular activities, specific scientific resources, student behavior that hinders learning, science classroom discipline, perception of teacher injustice, and science extracurricular activities are important contextual factors that affect students' scientific literacy.

(2) Compared with non-family socioeconomically disadvantaged students, students from socioeconomically disadvantaged families face more shortage of educational materials, more shortage of teacher resources, and more student behaviors that hinder learning, and they have fewer creative extracurricular activities and specific scientific resources, etc.. At the same time, socioeconomically disadvantaged students are also facing a worse scientific classroom discipline environment and less opportunities to participate in science extracurricular activities. The cumulative contextual risk and individual cumulative contextual risk in school are significantly higher than those of non-family socioeconomically disadvantaged students.

(3) With the increase of the cumulative contextual risk index, the distribution of socioeconomically disadvantaged students and non-family socioeconomically disadvantaged students in China has shown a gradual decline, but the proportion of non-family socioeconomically disadvantaged students is higher than that of non-family disadvantaged students at each cumulative risk level, except for when the cumulative risk index is 0.

(4) Under the condition of controlling gender and grade,for Chinese socioeconomically disadvantaged students, each increase in individual cumulative contextual risk by one unit will reduce the scientific literacy by 13.24 points, while each increase in cumulative contextual risk in the school field will result in 11.54 points’ drop of scientific literacy.

(5) The relationship between individual and school cumulative risks with students’ scientific literacy is linear, showing a “gradient effect”.

3. There are differences in the protective effect of scientific learning enjoyment, scientific learning interest, self-achievement motivation, and scientific learning time on scientific literacy, and the effect of cumulative individual protective factors is limited.

(1) The enjoyment of scientific study and the time of scientific study have a “compensation effect” on the scientific literacy of the Chinese socioeconomically disadvantaged students, while the interest in scientific learning and self-achievement motivation have a “protective effect”.

(2) At the same risk level, the greater the number of protection factors, the higher the score of scientific literacy; In a group with the same cumulative number of protection factors, as the number of risk areas increases, both more risk factors and less protection factors will lead to a decrease in the individual's scientific literacy