The sports injury refers to the injuries in the process of the sports. There are many reasons for the injuries, which can be divided into the direct causes and the incentives. The direct causes include the lack of attention ideologically, the lack of the reasonable warming-up, the technical errors, the heavy sports load, the bad physical functions and mental states, the improper methods of the organizations, the rough sports or the violation of the rules, the defects of the venues and equipment, and the influence of the bad weather and so on. And the incentives include the two aspects of the technical features of various sports and the physiological characteristics of the local anatomy. Therefore, we should pay attention to the prevention of the sports injuries. In this paper, the author carries on the analyses, researches and discussion from the causes and the prevention of the sports injuries, which has important significance to the improvement of the sports training and the organization of all kinds of the sports competitions.