Objective:To investigate the clinical diagnostic value of MRI retention enema cannula enhanced scanning in the high complex anal fistula.Methods:The clinical data of 60 anal fistula patients underwent surgery treatment from May 2020 to May 2022 in Affiliated Hospital of Shanxi University of Traditional Chinese Medicine were retrospectively analyzed. All patients underwent MRI plain scanning and enhanced scanning before operation. Compared with the surgical results, the difference between MRI plain scanning and enhanced scanning in the diagnosis of high complex anal fistula was compared.Results:All of the 60 patients successfully completed surgical treatment, and 58 cases internal orifices, 55 cases complex anal fistulas and 53 cases high anal fistulas were found intraoperatively. MRI plain scanning results showed 32 cases internal orifices, 46 cases complex anal fistulas and 42 cases high anal fistulas were found. MRI enhanced scanning results showed 54 cases internal orifices, 53 cases complex anal fistulas and 50 cases high anal fistulas were found. Based on surgical results, the coincidence rates of internal orifice, complex anal fistula and high anal fistula in MRI enhanced scanning were significantly higher than those in MRI plain scanning: 93.10% (54/58) vs. 55.17% (32/58), 96.36% (53/55) vs. 83.64% (46/55) and 94.34% (50/53) vs. 79.25% (42/53), and there were statistical differences ( χ2 = 21.76, 4.95 and 5.27; P<0.01 or <0.05). Conclusions:The MRI retention enema cannula enhanced scanning has obvious advantages in the diagnosis of high complex anal fistula, which provides scientific reference value for the diagnosis and operation of high complex anal fistula in clinic.