Abstract: According to the data obtained from simulated tests in laboratory,the s studies the average velocity of bedrock water flow in a single fracture within 3mm width in different condition,and establishes statistics equations of the average velocity and hydraulic gradient.A new test proof has been provided for testing the average velocity equations about bedrock water flow in the void between surfaces of rock’s continuity interrupted.And the application scope of the theory about bedrock water flow in the void has been enlarged.