Abstract: WC3J (D) type integral type explosion-proof rubber tyred vehicle brake torque and parking braking torque were obtained by calculation, a detailed analysis of the before and after bridge brake structure and working principle, working principle and characteristics of the fully hydraulic wet braking system are described. Through the theoretical analysis and practical application show that WC3J (D) type explosion-proof rubber tyred vehicle hydraulic brake system design is reliable and feasible, and can meet the requirements of coal mine vehicle braking performance and explosion-proof performance.