Objective To investigate the maternal function of primiparas, and to analyze itsrelationship with self-efficacy and subjective well-being,so as to provide a reference for developing targeted intervention. Methods A total of 297 primiparas were selected by convenience sampling when they came back to hospital for a check at 42 days after delivery, then they were investigated by using a general information questionnaire, the Chinese version of Barkin Index Maternal Functioning Scale, the General Self-Efficacy Scale and the General Well-Being Schedule. Results The participants′ total score of maternal function was (61.70±7.36), their score of self-efficacy was (25.16±4.09), and the score of subjective well-being was (67.62±7.88). Pearson correlation analysis showed that,the participants' score of self-efficacy and subjective well-being were positively correlated with the total score and each subscale score of maternal function (all P<0.05). Hierarchical regression analysis showed that, self-efficacy and subjective well-being could independently explain 18.4% of the variation in maternal function (both P<0.05). Conclusion The maternal function of primiparas is at a medium and above level, which is closely related to their self-efficacy and subjective well-being. When carrying out postpartum nursing care for primiparas, medical staff should give them enough information support and emotional support to improve their self-efficacy and subjective well-being, so as to promote the implementation of maternal function.