Objective To systematically evaluate the effectiveness of nasal septum mucosal flap for postoperative reconstruction of post-radiation nasopharyngeal necrosis (PRNN).Methods English databases, such as PubMed, Cochrane Library, Embase, Web of Science, and Chinese databases, such as CNKI, Wanfang, VIP were searched by computer. The retrieval time was from the establishment of the database to Feb 1, 2021. To search the clinical studies of repairing nasopharynx defect after operation of PRNN with nasal septum mucosal flap. Two researchers independently screened the literatures and extracted the data, then the analysis was carried out using the software Rstudio. The outcome index was the effectiveness of nasal septum mucosal flap in repairing nasopharyngeal defect. In addition, studies of PRNN treated by debridement of nasopharyngeal necrotic tissue were searched and analyzed as reference.Results A total of 1005 literatures were retrieved initially. According to the inclusion and exclusion criteria, 5 single-arm studies were included, including 145 patients. The success rate of reconstruction of nasopharyngeal defects by nasal septum mucosal flap was 84% (95%CI=[0.71,0.93],I²=53.75%). At the same time, 9 studies of PRNN treated by debridement of nasopharyngeal necrotic tissue revealed an epithelization rate of 47% (95%CI=[0.31,0.62],I²=94%).Conclusion Nasal septum mucosal flap can be used as an effective repair material to reconstruct defects after debridement of PRNN. More prospective cohort studies or randomized controlled trials are needed for further study.