Adhesive capsulitis (also known as frozen shoulder) is a common clinical shoulder disorder and can be effectively improved through physical rehabilitation. With advancements in technology, virtual reality (VR) has been increasingly employed in rehabilitation treatments. However, most relevant studies have merely employed traditional assessment tools to assess the therapeutic effects rather than the substantial amount of motor trajectory data or task performance collected by motor training systems. In this research, an innovative frozen shoulder rehabilitation system using a Microsoft Kinect sensor and VR was successfully developed and five task-oriented motor indices and task performance were proposed to assess motor performance. A clinical experiment involving twenty patients was conducted. Objective clinical assessment outcomes verified the effectiveness of the developed system for frozen shoulder rehabilitation. The improvements assessed according to motor indices and task performance were consistent with the objective clinical assessment results. Furthermore, correlation analysis showed that several items in the task performance and motor indices were significantly correlated to clinical assessment items. Moreover, numerous items in the task performance and motor indices capable of predicting the clinical assessment results were identi-fied through stepwise regression analysis. The results of this research can facilitate the subsequent development of new assessment methods.