Objective：This study aims to explore the factors that influence parenting stress among mothers of second-born children in two-child families. It seeks to examine the relationship between maternal locus of control and the parenting stress associated with the second-born child, focusing also on the impact of the parent-child relationship with the second-born child and the parenting stress experienced with the first child. Methods: 499 mothers from two-child families were surveyed. Their maternal locus of control, the parenting stress with each child, and the parent-child relationship with the second-born child were assessed respectively. Results: ①The findings revealed that a mother’s locus of control significantly predicted parenting stress for both the first and second-born child, with a tendency towards an external locus of control being associated with higher levels of stress. ②The quality of the parent-child relationship with the second child mediated the relationship between maternal locus of control and parenting stress for the second child. ③The parenting stress experienced with the first child also served as a mediator, linking maternal locus of control to the parenting stress of the second-born child. Conclusion: A mother’s locus of control can indirectly influence her parenting stress regarding the second child, mediated through both the parent-child relationship with the second child and the parenting stress previously experienced with the first child.

目的：探讨二孩家庭中母亲次子养育压力的影响因素，验证母亲子女教育心理控制源与次子养育压力的关系，以及次子亲子关系和长子养育压力在其中的中介作用。方法：对499名二孩母亲进行问卷调查，由母亲完成子女教育心理控制源量表、养育压力量表及次子亲子关系量表。结果：(1)母亲子女教育心理控制源可以正向预测长子及次子养育压力，母亲越外控其养育压力越大；(2)次子亲子关系在母亲子女教育心理控制源和次子养育压力之间起中介作用；(3)长子养育压力在母亲子女教育心理控制源和次子养育压力之间起并行中介作用。结论：二孩母亲的子女教育心理控制源可以通过次子亲子关系及长子养育压力间接影响次子养育压力。