Based on the research of braking principle of motorcycle braking system, a dynamic disc brake model and a 7degree motorcycle model were constructed individually under simulation software: Matlab and MSC. ADAMS. According to the input and output relationships between these two models, a co-simulation model was constructed by the co-simulation function that presented by ADAMS; it made braking performance researches on the co-simulation model be carried out. By co-simulation running, motorcycle-braking performance including ride easiness has been studied under different handle conditions such as pulse brake handle and normal brake handle. Braking performance under different handle conditions was compared and a high quality design was acquired.