Objective: To investigate the effect of low-intensity ultrasound combined with breast massage on postpartum lactation, breastfeeding and uterine involution. Methods: A cohort of 148 postpartum women was allocated into two equal groups: a control group and an experimental group according to the different ways of intervention, each comprising 74 participants. The control group received manual breast therapy following delivery, and the observation group was given low-intensity ultrasound combined with breast massage intervention. The two groups were intervened continuously for 3 days and followed up for 42 days. The initial time of postpartum lactation, the amount of lactation 48 h after delivery and the degree of breast distending pain 48 h after delivery were recorded in the two groups. Serum prolactin levels were measured at 48 and 72 h after delivery. The breastfeeding rate and uterine involution were compared between the two groups. Results: Compared with the control group, the lactation initiation time of the observation group was earlier (P<0.05), and there was a higher breast milk volume at 48 h postpartum (P<0.05). Compared with the control group, the observation group’s breast distending pain degree was lighter at 42 h after delivery (P<0.05). Compared with the control group, at 48 and 72 h after delivery, the observation group’s serum prolactin levels were increased (P<0.05). At 42 days after delivery, the observation group’s breastfeeding rate was higher compared with the control group (P<0.05). Compared with the control group, the uterine fundus of the observation group decreased at 3 days after delivery (P<0.05), and the rate of uterine involution at 42 days after delivery decreased (P<0.05). Conclusion: The synergistic intervention of low-intensity ultrasound combined with breast massage can effectively promote postpartum lactation function, relieve breast congestion and swelling pain, improve the success rate of breastfeeding, and promote uterine involution.