INTRODUCTION: Intrauterine adhesions (IUAs) are one of the most common causes of uterine infertility. Hysteroscopic adhesiolysis is the primary treatment for IUA, but the rate of IUA recurrence is high in moderate to severe cases. While traditional guidelines recommend placing a non-copper stainless steel intrauterine device (IUD) into the uterine cavity after adhesiolysis to prevent readhesion, the preventive effect is uncertain. Our preliminary trials suggested that the collagen scaffold was more effective in moderate cases. This study aims to assess the efficacy and safety of a collagen scaffold versus IUD in preventing readhesion after hysteroscopic adhesiolysis in patients with moderate IUA. METHODS AND ANALYSIS: This multicentre, open-label, randomised controlled trial evaluates the efficacy and safety of a collagen scaffold compared with an IUD in preventing readhesion after hysteroscopic adhesiolysis in women with moderate IUA. This trial will be conducted at six teaching hospitals and plans to enrol 200 participants. The primary outcome is the non-recurrence rate of IUA 2 months after adhesiolysis. Secondary endpoints include changes in American Fertility Society scores before and after surgery and postoperative menstrual blood volume. The 95% CIs for the difference in non-recurrence rates between the two groups will be calculated. If the lower limit of this interval exceeds the superiority threshold of zero, the conclusion of superiority is confirmed. ETHICS AND DISSEMINATION: This study has received approval from the ethics committee of the Affiliated Drum Tower Hospital of Nanjing University Medical School (2022-491-02) and the ethics committees of the participating centres. Written informed consent will be obtained from each participant before starting any study procedures. The results of this trial will be published in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: ChiCTR2300068271.