Recently, a complex anal fistula was admitted to the ward after being transferred from an outside hospital. He had painful paranal swelling and recurrent pus flow for more than a year. On examination, there were 12 external openings and 2 internal openings. After ruling out inflammatory bowel disease and tuberculosis, surgical treatment was decided. Surgical attention was paid to the relationship between open curettage and preservation of anal function. Pre-surgical incision selection. As shown in the figure: surgical picture The surgery was performed with main focal incision Hanging wire; para-oral drainage; high position tube. One month after surgery All the patient’s anal function was normal.