The working principle of the hydraulic transmission device: (1) The prime mover drives the centrifugal pump to rotate, sucks liquid through the water inlet pipe, and is accelerated in the centrifugal pump to obtain kinetic energy. (2) The centrifugal pump drives the liquid with a certain kinetic energy to enter the turbine through the conduit, impacts its blades to rotate the turbine, and outputs the rotary motion through the turbine shaft. (3) The speed of the liquid discharged from the turbine is reduced, and the kinetic energy is reduced.