The present invention is a diesel-can improve the ignition instability problems in knocking problems and low load operation region in a high-load operation region in the formed gasoline mixed combustion engine relates to a combustion control method of the formed engine gasoline mixed combustion, diesel It will have the primary purpose to provide a combustion control method and apparatus. To achieve the above object, in the in the diesel and mixed combustion mode, the combustion control method of an engine having a gasoline combustion mode to burn only the gasoline fuel mixture combustion is made of gasoline fuel, a mixed combustion mode and a gasoline combustion mode, the engine determining the combustion mode according to the state of the operation state; Determining a compression ratio corresponding to the combustion mode according to the state of the operation state of the engine; Step to control the operation of the variable compression ratio device for controlling the compression ratio of the cylinder to the determined compression ratio; Comprising: a combustion state of the engine determined for control of the post-combustion to the compression ratio determining whether satisfy conditions set to ensure the combustion stability; And does not satisfy the set condition the combustion pressure sensor signal a feedback signal to the set condition and performing the compression ratio correction by the variable compression ratio device so as to satisfy; combustion engine having a mixed combustion mode, and a control method, and this It provides a combustion control device for implementation.