Background: Although corticosteroid injection remains a common first-line treatment of trigger finger, but not all cases of trigger finger respond the same. This study aims to compare the clinical effectiveness of ultrasonography-guided corticosteroid injection with and without needle knife release of A1 pulley in treating trigger finger. Methods: 49 patients with trigger fingers (55 fingers, thumb) were included in this study. 28 fingers underwent ultrasonography-guided corticosteroid injection plus needle knife release of A1 pulley (combination group), and 27 fingers underwent only ultrasonography-guided needle knife release of A1 pulley (monotherapy group). Visual analogue scale (VAS), Froimson scale, postoperative recurrence rate, and thickness of A1 pulley in pre-operation and follow-up period were recorded. Results: Higher clinical amelioration and clinical cure rate were observed in combination group at 2 weeks after treatment among patients with Froimson scale Grade III and IV (p<0.05). Among Grade IV patients, combination group had narrower thickness of A1 pulley and better pain relief at 2 weeks postoperatively (all p<0.05). There was no significant difference regarding the values of clinical amelioration rate, clinical cure rate, thickness of the A1 pulley, pain relief and recurrence rate between the two groups at 12 week and 6 months postoperatively (all p>0.05). Conclusion: Ultrasonography-guided corticosteroid injection combined with needle knife release of A1 pulley had superiority in early-stage pain relief and narrowing the thickness of A1 pulley than single needle knife release, but its medium and long-term effects were not obvious.