Background: Breastfeeding is the most effective way to provide food for the healthy growth and development of babies. It has been reported in the literature that interventions on parturients, with the theory of planned behavior (TPB) as the guiding framework, can achieve good results. The purpose of the present study was to explore the effect of the TPB on primipara breastfeeding.Methods: A total of 70 primiparas, who were given regular intervention mode at Haian People's Hospital from May 2017 to May 2018, were selected as the control group, and a total of 70 primiparas, who were given the TPB model from June 2018 to June 2019, were selected as the observation group. Exclusive breastfeeding rates, continuous breastfeeding rates, and breastfeeding confidence and breastfeeding impact factors were compared between the two groups.Results: After the intervention, the pure breastfeeding rates of the observation group at discharge, 1 month after delivery, and 4 months after delivery were higher than those of the control group (P<0.05).After intervention, the continuous breastfeeding rates of the observation group was higher than that of the control group at 4 months after delivery (P<0.05). After intervention, the skill dimension, inner activity dimension, and total score of the observation group were higher than those of the control group (P<0.05).After intervention, scores of attitude, perceptual behavior control, and knowledge in the observation group were higher than those of the control group (P<0.05). Conclusions:The application of the TPB to primipara breastfeeding can significantly increase the rate of exclusive breastfeeding and continuous breastfeeding, and effectively improve the impact factors of breastfeeding.