Gear transmission with meshed medium belt is proved feasiable which is, with lower vibration and noises, lower cost and energy saving. To realize "green lubrication". In the type of gear transmission, the medium belt is the feature component, also is one of the key components. The life of medium belt has great effects on the efficiency and performance of the whole transmission. However, in the process of transmission the medium belt is subjected to great tension stress, and easy to break. So we take measures to analyze the tension stress ,compression and friction forcel of the medium belt at first, and take it as the inference to select the materials of the medium belt.