The utility model discloses a double rotation speed diesel engine for power generation, which comprises a diesel engine body, a controller and a control switch, wherein the controller is connected to the diesel engine body through wires, the control switch is connected to the controller through the wiring harnesses, and the control switch implements switch control of the controller to the rotation speed of the diesel engine by switching the diesel engine between a working rotation speed and the idle speed according to the load requirements of the diesel engine. The diesel engine of the utility model has reduced integrated oil consumption, and can realized the effect of energy saving and emission reduction.