Abstract: For the problems of the transmission parts damage and sliding accident in using the mine vehicle，the principle and composition of the vehicle transmission system and the brake system were analyzed，and the behavior in the service of vehicles were investigated.In order to avoid from the transmission parts damage and sliding accident again，a pressure-relief device which could relieve the pressure of hydraulic braking system was developed to cut off the power in transmission and to realize the power cutoff in power gearshift gear-box，and then the load of transmission parts were reduced in the braking process.The 2-position 3-way hydraulic operated directional valve was used to realize the automatic braking function in the flameout of the engine.Results showed that：the damage on transmission parts including transmission shaft，transmission clutch friction plate and other parts were reduced effectively by using the pressure-relief device，and sliding accident never happened by adopting 2-position 3-way hydraulic operated directional valve.Through these measures，the safety and reliability in operating the mine vehicle were improved.

Key words: Mine vehicle, Hydraulic brake, Power cutoff, Automatic braking, Coordination control