The invention discloses a diesel engine with plateau power performance being improved. The diesel engine with the plateau power performance being improved comprises a diesel engine body, an engine intake manifold, an engine intake main pipe, a supercharger, an air filter and a supercharging device. The engine intake manifold is arranged on the intake side of the diesel engine body, and one end ofthe engine intake manifold communicates with various cylinders of the diesel engine body. The engine intake main pipe communicates with the other end of the engine intake manifold. The gas outlet endof the supercharger is connected with the engine intake main pipe. The air filter is arranged at the intake end of the supercharger. The supercharging device comprises an electric control pumping device and an electric control unit, the gas outlet end of the electric control pumping device is connected between the supercharger and the air filter, and the intake end of the electric control pumpingdevice communicates with the air filter. According to the diesel engine with the plateau power performance being improved, the plateau power performance of the engine is improved and reaches or is close to the plateau power level.