Objective To analyze the influence of attitude of second child on fertility intention and behavior. Method Through the research method of planned behavior theory, the questionnaire project of two-child fertility attitude was compiled. By means of stratified cluster sampling, 400 questionnaires were distributed to young women who had children in the counties of SQ city and LY city in northern jiangsu province. Results It is more acceptable for young women that having a second child will cause family conflicts, increase the burden of time and energy, and affect personal career development. Self-assessment of family economic status, educational background and working status has an impact on the attitudes of young women towards having a second child. There are non-deterministic causal relationships among the fertility intention, behavior and attitude of the second child. Conclusion The government should carry out targeted publicity and education for two-child birth, and formulate supporting policies for two-child birth as soon as possible. In particular, preferential policies for women in employment, medical treatment and education for infants and young children should be formulated and implemented as soon as possible, so as to effectively ease the pressure on young women to have two children.