Engine control method of hybrid vehicle, engine control system of hybrid vehicle and hybrid vehicle

The invention discloses an engine control method of a hybrid vehicle, an engine control system of the hybrid vehicle and the hybrid vehicle, wherein the method comprises the following steps that: when the hybrid vehicle enters a series mode from a pure electric mode, an ISG (Integrated Starter Generator) is controlled to enter a torque control mode, and an engine is dragged by a preset torque; when the rotating speed of the engine reaches the preset rotating speed, the ISG is controlled to enter a rotating speed control mode, so that the ISG is controlled; and after the preset time is over, the engine is controlled to spray oil until the input torque of the engine reaches the target torque, and the starting of the engine is completed. The control method provided by the embodiment of the invention has the advantages that the vehicle starting and stopping performance can be improved, so that the starting of the engine is smooth; the torque switching of the engine and the motor are smooth after the starting succeeds; energy sources are saved; and the use experience of users is improved.