由于双职工家庭的增多，近七成的祖辈会参与对幼儿的养育，祖辈与父母形成了代际 共同养育家庭。但在形成稳定的代际共育家庭之间，祖辈可能会在核心家庭中反复的进出，形成祖辈养育变动情况，但鲜有研究探索祖辈养育变动对幼儿适应的影响及其内在机制。 因此，本研究基于生命历程理论视角与共同养育生态理论框架，探讨祖辈养育变动轨迹（分 离次数、分离时长、转换次数以及轨迹类别）对幼儿社会适应的影响，以及代际共同养育 关系在其中的中介作用。

本研究选取了 256 个有幼儿的代际共同养育家庭，采用回溯性问卷收集了幼儿出生后 前三年祖辈的养育情况，用序列分析对祖辈养育变动轨迹进行了描述性分析；同时用问卷 调查法测查了幼儿社会适应和母亲、祖辈的共同养育关系质量，并分别从变量中心和个体 中心的视角检验了祖辈养育变动轨迹对幼儿社会适应的影响，以及探讨了母亲和祖辈的共同养育关系的相对中介作用。研究结果发现：

(1)总体而言，在幼儿出生的前三年内，大部分祖辈都会稳定地参与养育幼儿，祖辈发 生分离和转变的次数相对较少。通过序列分析提取出三种典型的祖辈养育变动轨迹模式： 奶奶稳定组，外稳内变组，祖辈分离，其中奶奶稳定组的家庭数量最多。

(2) 从变量中心的视角，祖辈养育变动轨迹特征标中的总体混乱程度（熵）能够显著负 向预测幼儿的能力表现。并且不同的祖辈养育变动轨迹特征会对母亲和祖辈的共同养育关 系有差异性的影响。对母亲而言，分离时长能够显著预测母亲更少的共同养育认可和更多 的共同养育矛盾暴露；但对于祖辈而言，过往养育经历中的分离次数和转换次数才能显著 地预测祖辈的共同养育关系。

(3) 从个体中心的视角，祖辈分离组幼儿的能力要显著高于奶奶稳定组和外稳内变组， 而奶奶稳定组和外稳内变组在幼儿能力基本无差异；幼儿情绪与行为问题上三组之间无显 著差异。在代际共同养育关系上，总体而言奶奶稳定组和外稳内变组呈现相同的模式，而 祖辈分离组与其他两组间存在差异。相比于祖辈分离组，外稳内变组和奶奶稳定组母亲对祖辈有更高的共同养育认可、更少的代际共育破坏和矛盾暴露。

（4）相对中介分析结果均显示只有母亲报告的代际共同养育关系中介作用显著：在幼儿能力方面，奶奶稳定组和祖辈分离组在共同养育认可的相对中介显著，外稳内变组和祖辈分离组在共同养育认可和共同养育矛盾暴露显著；在幼儿情绪与行为问题方面，奶奶稳定组和祖辈分离组在共同养育破坏的相对中介显著，外稳内变组和祖辈分离组共同养育认可、共同养育破坏和共同养育矛盾暴露显著。

本研究从生命历程理论的时序性视角出发，探索性地描绘了早期祖辈养育变动轨迹特征以及典型模式，同时基于共同养育生态模型进一步验证了祖辈养育变 动轨迹、代际共同养育关系和幼儿社会适应之间的关系。研究结果强调，在代际共同养育家庭中，要关注早期祖辈养育变动轨迹的影响，母亲和祖辈要注重建立积极的共同养育关系，以及发挥母亲在其中的主导性作用，以更有效地促进幼儿的社会适应。

Due to the increase in dual-earner families, nearly 70% of grandparents will be involved in the parenting of young children, and grandparents form intergenerational co-parenting families with their parents. Before the formation of stable intergenerational co-parenting families, grandparents may move in and out of the nuclear family repeatedly, creating a grandparenting change situation. However, few studies have explored the effects of grandparenting changes on toddler’s adjustment and their underlying mechanisms. Therefore, this study explores the impact of grandparenting change trajectories on toddler 's social adjustment and the mediating role of intergenerational co-parenting relationships based on life course theory and co-parenting ecological theory framework. In this study, 256 intergenerational co-parenting families with toddlers were selected, and the grandparents' parenting in the first three years of life was collected using a retrospective questionnaire. We also examined the effects of grandparental changes on young children's social adjustment and the relative mediating role of maternal and grandparental co-parenting relationships from variable-centered and individual-centered perspectives. The findings found that:

(1) Overall, most grandparents are steadily involved in parenting toddlers during the first three years of life, with relatively few grandparental separations and shifts. Three typical patterns of grandparenting change trajectories were extracted from the sequence analysis: group1=stable paternal grandmother, group2=grandparent separation, group3= stable maternal grandmother, with the largest number of families in the group1.

(2) From the center-of-variable perspective, the overall disorganization (entropy) in the grandparenting change trajectory feature scale can significantly and negatively predict the ability performance of toddlers and different grandparenting change trajectory characteristics can have differential effects on the co-parenting relationship between mothers and grandparents. For mothers, the length of separation significantly predicted less maternal co-parenting approval and more co-parenting conflict exposure; however, for grandparents, it was the number of changes in past parenting experiences that significantly predicted grandparental co-parenting relationships.

(3) From an individual-centered perspective, the ability of toddlers in the group2 was significantly higher than that of the group1 and the group3, whereas there was essentially no difference in the ability of toddlers in the group1 and the group3; there was no significant difference between the three groups on emotional and behavioral problems of toddlers. In terms of intergenerational co-parenting relationships, the group1 and the group3 showed the same pattern overall, while there were differences between the group2 and the other two groups. Compared with the group2, mothers in the group3 had higher co-parenting recognition and less intergenerational co-parenting disruption and conflict exposure.

(4) The results of the relative mediation analysis showed that only mothers reported significant mediation of intergenerational co-parenting relationships: in terms of toddler's ability, the relative mediation of co-parenting approval was significant in the group1 and group2, and co-parenting approval and co-parenting conflict exposure was significant in the group3 and the group2. In terms of emotional and behavioral problems, the group3 and group2 were significant in co-parenting recognition, co-parenting disruption, and co-parenting conflict exposure.

This study explored the characteristics and typical patterns of early grandparenting change trajectories from the chronological perspective of life course theory, and further validated the relationships among grandparenting change trajectories, intergenerational co-parenting relationships, and toddler's social adjustment based on the ecological model of co-parenting. The findings emphasize that in intergenerational co-parenting families, it is important to pay attention to the influence of early grandparenting change trajectories, and mothers and grandparents should focus on establishing positive co-parenting relationships and the leading role of mothers in them to more effectively promote toddler 's social adjustment.