Friction property plays an important role in the operating process of engine, the analysis and discuss about friction property can help to improve the operating performance of engine. Based on the basic structure of swash-plate engine, the sphere rolling friction model and the roller rolling friction model were established, and corresponding formulae of the rolling friction force and the rolling friction coefficient were deduced. Then as an application, we employed the exact parameters of a swash-plate engine to calculate the sphere rolling friction force, the sphere rolling friction coefficient, the roller rolling friction force and the roller rolling friction coefficient. According to comparison, we concluded that roller rolling friction force was far less than sphere rolling friction force, and roller rolling friction coefficient was far less than sphere rolling friction coefficient. Furthermore, we proposed two topics which would be our next study concerning engine friction property: friction-induced heat, and high temperature influence on friction property.