Objective To study the clinical efficacy, advantages, and disadvantages of adaptive biofeedback training combined with oral administration of compound polyethylene glycol 4000-electrolyte powder in the treatment of children with outlet obstruction constipation (OOC). Methods A total of 168 children with OOC were enrolled in this prospective study. All the subjects were randomly divided into a test group and a control group based on the order of visiting time, 84 in each group. The test group was treated with adaptive biofeedback training combined with oral administration of compound polyethylene glycol 4000-electrolyte powder, and the control group was treated with oral administration of compound polyethylene glycol 4000-electrolyte powder alone. Eleven children in the test group and two children in the control group withdrew from the study since they could not finish the whole treatment course. Finally, 73 children in the test group and 82 children in the control group were included in this analysis. As clinical outcomes, the total score of clinical symptoms and overall response rate were compared between the two groups at weeks 4 and 8 of treatment. Results There was no significant difference in the total score of clinical symptoms between the two groups at beginning of treatment and at week 4 (P>0.05), while the test group had a significantly lower total score of clinical symptoms than the control group at week 8 (P<0.05). At week 4, there was no significant difference in overall response rate between the two groups (P>0.05), while the test group had a significantly higher overall response rate than the control group at week 8 (P<0.05). Conclusions Adaptive biofeedback training combined with oral administration of compound polyethylene glycol 4000-electrolyte powder is significantly associated with improvement of clinical outcomes in the treatment of children with OOC.