Objective：To observe the clinical effect of ultrasound-guided hook needle knife release method for stenosing tenovaginitis of flexor tendon.Methods：Divided 100 cases of patients into the treatment group and the control group randomly，with 50 cases in each group；the control group was treated with traditional hook needle knife release method and the treatment group was treated with ultrasound-guided hook needle knife release method；followed up the patients in one week，one month and three months after the operation，compared the scores of system evaluation method of the total active degree(TAM)，the scores of motion pain，tenderness and flexor resistance pain，the postoperative recurrence rate and the incidence of complications in the two groups before and after treatment.Results：At one week，one month and three months after the operation，the scores of motion pain，tenderness and flexor resistance pain of patients in the two groups showed a downtrend and significant differences were found in the multiple comparison of each time point before and after treatment(P ＜ 0.05)；at one week after the operation，all the scores in the treatment group were lower than those in the control group(P ＜ 0.05)；while there was no significant difference being found in the comparison of all the scores in the two groups in one month and three months after the operation(P＞0.05).Three months after the operation，the total effective rate of TAM system scores and the total effective rate of clinical effect were 98.0% and 98.0% respectively in the treatment group and 90.0% and 90.0% respectively in the control group，and no significant difference was found in the comparison between the two groups(P＞0.05).No complications or recurrent cases were found in the treatment group.The incidence of complications was 10.0% and the recurrence rate was 8.0% in the control group，compared the two groups，differences being significant(P＜0.05).Conclusion：The application of ultrasound-guided hook needle knife release method for stenosing tenovaginitis of flexor tendon has a more effective and safer curative effect when compared with traditional hook needle knife release method and is easier for the operator to master，which deserves the clinical promotion and application.