Abstract: Objective: To study rotation angle and compare with the effect of two immobilization methods of shoulder dislocation reduction.Methods: This was a retrospective study from January 2004 to August in 2009 for 93 patients with shoulder dislocation and treated in emergency departments. We measured the rotation angle of success reduction. Two methods for adduction immobilization(external and internal rotation) were used and results of shoulder function and recurrence rates were analyzed. Results: We found the rotation angle of success reduction were adduction about 20±3?, internal rotation about 24±15?；anteflexion about 34±3?.Recurrence rate of internal and external immobilization was 28.6%,13.5%,respectively(P<0.05). There was not statistically significant for Joint function DASH score in two groups.Conclusion:. External rotation immobilization may be more effective for Joint function recovery and less recur than internal’s for shoulder dislocation treatment in emergency departments. The scope of rotation angles of reduction has value to reduction methods.