Objective To investigate the factors influencing undergraduate nursing students′ autonomous learning ability, and to establish a structural equation model for the paths among the variables. Methods A total of 447 undergraduate nursing students from nursing schools of 6 comprehensive universities in Henan province were selected and asked to fill out the demographic questionnaire, the Autonomous Learning Ability Scale, the Online Learning Environment Scale and the Academic Self-efficacy Scale. Results The students scored (67.21±16.46) points in autonomous learning ability. Structural equation model analysis showed that the 3 dimensions of online learning environment (learning contents, learning support, learning social structure) had direct and indirect(through the mediating role of academic self-efficacy) impact on autonomous learning ability; academic self-efficacy also had direct impact on autonomous learning ability（β=0.523,P＜0.01）. Conclusion The online learning environment can directly influence students′ autonomous learning ability, and also can exert indirect influence on autonomous learning ability through the mediation of academic self-efficacy. Measures should be taken to enhance the building of online learning environment for nursing students, as well as their academic self-efficacy,so as to improve their autonomous learning ability.