The invention relates to a solar-energy hydraulic transmission device which comprises a coil heat-exchange tube, a tile-type heat-exchange plate, a heat insulating layer, a liquid-gas separator, an oil tank, an oil pipe, a ring-pull, a cylinder, a piston, a spring, an adjusting screw and a valve. The solar-energy hydraulic transmission device makes use of the function of solar energy to the heat-exchange tube and the heat-exchange plate and causes the containment of ammonia filled in the heat-exchange tube to be changed so as to generate oil pressure which causes the piston to drive a valve stem in the ring-pull, thereby controlling the on-off of the valve and guaranteeing the normal operation of a solar-energy water heater or the normal start-up of the on-off of the ventilation window of a warehouse. The solar-energy hydraulic transmission device use the function that the tile-type heat-exchange plate can be heated on both sides and use the heat insulating layer to remove the peak value of high pressure and to level up the valley value of low pressure; therefore, working pressure tends to smoothness, the operation is safe and liable, and the manufacturing cost is low. The solar-energy hydraulic transmission device can control the working pressure, realize the synchronal operation with the solar-energy water heater, and serves as a ventilation switch for the requiring of the indoor temperature control without electricity supply. When the room temperature reaches a certain degree, the solar-energy hydraulic transmission device can automatically open the windows to allow ventilation and give alarms.