Background: Trigger finger is a common cause of disability and pain in the hand and The lines of management of this disease start by conservative treatment as rest, NSAID, local corticosteroid injection under the tendon sheath either blind or by musculoskeletal ultrasound guidance and surgery may indicated in recurrent cases. Aim of the study: The aim of the present study was to evaluate the musculoskeletal ultrasound accuracy to guide the injection of corticosteroid in trigger finger management. Material and methods: 50 cases that complaint from symptoms of trigger digit in this randomized, prospective control study were recorded. All the cases were injected by 1 ml corticosteroid 1ml of 2% lidocaine at the level of the A1 pulley under the tendon sheath. The injection done under control of musculoskeletal ultrasound after a blinded needle insertion. Comorbidities and associated diseases were recorded. Follow up examinations at the 2 week and 6 months, no complications were recorded. The results were assessed according to the green's grading. The pain was assessed according to visual analogue scale. Results: The cases in the present study were assessed according to age, associated diseases and hand dominance. The female patients were more than male patients in the present study. The injection under control of musculoskeletal ultrasound accurate more than a blinded injection even when an expert physician who did it. And It showed the same efficacy according to green's grading at the period of follow up examinations when compared with the pre-injection status. No complications were seen during the period of the follow up. Conclusion: A different technique of injection using musculoskeletal ultrasound guidance all of which gave excellent accuracy superior to a blinded injection even when it is done by expert physician. However, the post injection result was similar to that of a blinded injection. Level one of evidence (randomized prospective study).