Objective To analyze the imaging manifestations of posterior dislocation of shoulder and to explore the mechanism of the injury. Methods The clinical features and imaging characteristics of 8 patients with posterior dislocation of the shoulder were analyzed retrospectively, and the pathogenesis of posterior dislocation of the shoulder was discussed. Results 8 cases of dislocation of the shoulder after X-ray film showing the performance of the hummers, is situated in the first place or function were internal rotation, the hummer large nodule probation, no abnormal joint space, “tear drop” shadow smaller; five patients a result of lateral film thoracic overlapping structure to identify unclear, three lateral humeral head shows that films backward shift. MSCT for the performance of the humeral head spins backwards, away from the limitations of the joints after the mend edge. Conclusion X-ray combined with MSCT can clearly display the change of dislocation of the shoulder joint, to accurately determine the direction of rotation and the humeral head prolapse degree and its relationship with the surrounding structures, it has important clinical value.