Abstract： Objective： To study the clinical effect of fine- needle aspiration of modified small- needle scalpel therapy guided by ultrasound for myositis ossificans induced by scapulohumeral periarthritis in active stage. Methods：A total of 52 cases of patients with myositis ossificans induced by scapulohumeral periarthritis and with ossification degree of gradeⅡwere selected and randomly divided into two groups， 26 cases in each group. The fine- needle scalpel group was inserted by 18G/21G- PTC puncture needle guided by ultrasound； the slope of needle tip was used to follow distribution direction of muscle fiber or tendon， and to conduct lysis between tendon and tendon sheath. The common needling group was given needling at tenderness points by acupuncture-moxibustion needle. The clinical effect，the scores of Visual Analogue Scale of pain(VAS)，the range of motion and the improvement of ossification degree under color Doppler ultrasound were observed in the two groups. Results：The total clinical effective rate was 92.31% in the fine- needle scalpel group，higher than that of 76.92% in the common needling group， the difference being significant(P＜0.05). After one， two and three weeks of treatment，the VAS scores of pain in the fine-needle scalpel group were lower than those before treatment，and those in the common needling group at the same period，differences being significant(P＜0.05). The range of motions such as abduction， anteflexion and posterior extension in the two groups were larger than those before treatment， and the range of motions such as abduction， anteflexion in the fine- needle scalpel group were larger than those in the common needling group， differences being significant(P＜0.05). The total effective rate of the improvement of ossification degree under color Doppler ultrasound was 80.77% in the fine- needle scalpel group and 50.00% in the common needling group，the difference being significant(P＜0.05). Conclusion：The fine- needle aspiration of modified small- needle scalpel therapy guided by ultrasound has good clinical effect in treating myositis ossificans induced by scapulohumeral periarthritis in active stage，and is superior to common needling therapy，which can alleviate pain，increase the range of motion，and improve ossification degree.