In the appointment of medical resource, The reserved capacity of the emergency patients plays a key role in medical appointment scheduling. This paper which is based on the massive data gathered by CT department in West China Hospital of Sichuan University analyzes the occupation data of CT department. The data are gathered in two ways: by hour and by day, and then this paper sets a model of them which is used to predict the capacity in the near future, Since the authenticity of the data and time series analysis of SAS software are widely applied, the model obtained in this paper can be used for hospital managers to guide the allocation of emergency patients and make reasonable allocation of medical resources effectively.