随着汉语教学实用化趋势凸显，商务汉语教学发展速度逐渐加快，针对商务汉语相关教学法的研究具有进一步发展的空间。通过教学实践，发现美国宾夕法尼亚州立大学（The Pennsylvania State University）商务汉语案例教学存在教学材料缺乏完整性、教学步骤不清晰、教学对象参与度较低等问题。为优化商务汉语案例教学，本研究基于案例教学法和专门用途外语教学相关理论，以宾夕法尼亚州立大学中高级商务汉语课程的案例教学为例，探索优化美国商务汉语案例教学的原则与方法等内容。具体包括以下六个部分：

第1章主要介绍了选题缘起、研究意义和研究方法，并对“商务汉语”进行概念界定，阐述专门用途外语教学和案例教学法相关理论，说明研究创新之处。

第2章以文献综述为主，对商务汉语、案例教学法应用于专门用途汉语教学、美国线上汉语教学相关研究进行梳理，发现关于美国线上商务汉语案例教学研究的不足之处。

第3章为案例教学法应用于商务汉语课程的前端分析，以宾夕法尼亚州立大学中高级商务汉语课程为例，从四方面分析教学现状，并调查学校汉语学习者的商务汉语学习需求，明确优化现有案例教学的必要性与可行性。

第4章为商务汉语案例教学总体优化设计，针对认知、技能、情感领域及学习策略四方面的教学目标，本着“以学习者为中心”、“以教师为主导”、“以案例为基础”的原则，对教学流程、案例主题、案例文本等方面进行总体优化。

第5章侧重商务汉语案例教学优化设计的实施与评估反思，展示“短视频行业的飞速发展”和“星巴克的‘第三空间’”两个案例教学实例，从不同角度进行教学反思，同时运用问卷调查对教学效果进行评估。

第6章从优势与不足两方面对优化后的教学情况进行评价，并针对美国商务汉语案例教学，从学校、教师与学习者三个主体出发提出具体教学建议。

最后得出结论：案例教学法符合商务汉语学习者的学习需要；学校、教师与学习者共同努力才可收获理想的商务汉语案例教学效果；商务汉语案例教学的优化能够提升学习者的汉语水平和能力，能够推动商务汉语教学的持续发展。

With the practical trend of Chinese teaching, the development speed of business Chinese teaching is gradually accelerating, and the research on business Chinese related teaching methods has further development space. Through teaching practice, I found that the business Chinese case teaching of The Pennsylvania State University had some problems, such as incomplete teaching materials, unclear teaching steps and low participation of students. In order to optimize business Chinese case teaching, I use Case Teaching Method and the theory of English for Specific Purposes to explore the principles and methods of optimizing business Chinese case teaching in the United States by taking the case teaching of CHNS412 of The Pennsylvania State University as an example. Specifically, it includes the following six parts:

Chapter 1 mainly introduces the reasons for the topic selection, research significance and methods, defines the key concept of "business Chinese", expounds the relevant theories of English for Specific Purposes and Case Teaching Method, and explains the innovation of the research.

Chapter 2 focuses on the literature review, including business Chinese, the application of Case Teaching Method in Chinese for specific purposes, and online Chinese teaching in the United States, to find the shortcomings of the research on online business Chinese case teaching in the United States.

Chapter 3 is a front-end analysis of the application of Case Teaching Method to business Chinese course. Taking CHNS412 of The Pennsylvania State University as an example, analyze the present situation of teaching from four aspects and investigate Chinese learners of business Chinese learning needs, to clarify the necessity and feasibility of optimizing the existing case teaching.

Chapter 4 is the overall optimization design of business Chinese case teaching. According to the teaching objectives in cognition, technique, emotion and learning strategy, the teaching process, case theme and case text are optimized in accordance with the principles of "learner-centered", "teacher-led" and "case-based".

Chapter 5 is the implementation and evaluation reflection of the optimization design of business Chinese case teaching. By showing two case teaching examples, "The rapid development of the short video industry" and "Starbucks' Third Space", the teaching reflection is carried out from different aspects, and the teaching effect is evaluated by questionnaire survey.

Chapter 6 evaluates the optimized teaching situation from two aspects of advantages and disadvantages, and puts forward specific teaching suggestions from the three subjects of schools, teachers and learners for business Chinese teaching in the United States.

Finally, the study found that Case Teaching Method meets the learning needs of business Chinese learners. Schools, teachers and learners can make joint efforts to obtain the ideal effect of business Chinese case teaching. The optimization of business Chinese case teaching can improve learners' Chinese level and ability, and promote the sustainable development of business Chinese teaching.