Abstract: Using the methods of interview and observation, this paper, based on a qualitative research paradigm, deeply analyzes the reasons for the formation of urban married and child-bearing women's physical fitness motivation and the process and mechanism of motivation transformation in the fitness process. It shows that urban married and child-bearing women's physical fitness motivations include physical management, promotion of interpersonal relationships, improvement of mental state, and seeking guidance and supervision, but during the fitness process, participants' fitness motivation is influenced by external stimulation and support, sports cognition and behavior changes, internalized or restricted physical and mental development too. It is believed that the restrictive factors for urban married and child-bearing women to participate in physical fitness still exist, and their rights and status should be reconstructed from the perspective of social and cultural environment, and the internal motivation of physical fitness should be improved.