The invention relates to a temperature rise control system of a dump truck hydraulic system. The temperature rise control system of the dump truck hydraulic system comprises a first constant displacement pump, a second constant displacement pump, a first filter, a second filter, a first unloading valve, a second unloading valve, a first one-way valve, a second one-way valve, a third one-way valve,a stop valve, an electromagnetic valve, an energy accumulator and a pressure sensor. As a typical clearance working mode is adopted in an electric drive dump truck, lifting, steering and braking areall clearance working, and non-working time including parking idle time is much larger than working time. An electric unloading control mode is adopted, so that the constant displacement pumps are ina zero piezoelectric unloading state under non-lifting and non-steering and non-braking working conditions, so that calorific value is greatly reduced, temperature rise of the hydraulic system is inhibited, energy is saved, consumption is reduced, and the performance and service life of the hydraulic system are ensured.