System and method for controlling temperature of hydraulic oil tank

The invention provides a system for controlling the temperature of a hydraulic oil tank, which comprises an engine 1, the engine 1 is connected with a hydraulic pump 2, the hydraulic pump 2 is connected with a heat dissipation device 3, the heat dissipation device 3 is connected to the hydraulic oil tank 5 through an electromagnetic valve 4, and the oil outlet end of the electromagnetic valve 4 is connected to the hydraulic oil tank 5 through a heat exchanger 6. A temperature sensor 7 is arranged in the hydraulic oil tank 5, an input end of the controller 8 is connected with the temperature sensor 7, and the electromagnetic valve 4 is connected to an output end of the controller 8. A group of two-position four-way electromagnetic valves are additionally arranged on the basis of air-cooled heat dissipation of the oil drainage port of the hydraulic pump of the hydraulic oil tank, and different passages of the electromagnetic valves are controlled by the controller based on the temperature in the hydraulic oil t