A test system of water-sand permeability in fractured rock was used to explore the hysteresis of water-sand flow between two parallel fracture plains, the characteristics about the closed seepage velocity-pressure gradient curve were analyzed, and the reasons of hysteresis were discussed. The results show that, 1) when seepage velocity increase from 0 to 1.77 mm/s then decrease to zero, the velocity-pressure gradient curve forms closed-loop; 2) because of the difference in opening and roughness of fracture, and difference in concentration and particle size of sand, the hysteresis curves take on several shapes, include convex shaped loop, crescent shaped loop, dipper shaped loop, “8” shaped loop, and Crack shaped loop; 3) the main reasons for hysteresis is that the distribution in the flow velocity of water-sand through the fracture on the back trip is different from that on the forward trip owing to change of the contact angle among water, sand and rock fracture surfaces; 4) the important reasons for hysteresis include the deposit of sand grain on the fracture, the changes within the flow regime of water-sand in the fracture, and the viscoplasticity of water-sand mixture, etc.