The invention discloses a homogeneous compression ignition type internal combustion engine and a control system and a control method thereof. The internal combustion engine comprises a cylinder and a cylinder cover, a combustion chamber is arranged in the cylinder and above a piston; a combustion chamber volume instant regulating plunder capable of longitudinal moving and positioning on the cylinder cover is arranged on the cylinder cover and above the combustion chamber; the upper end of the combustion chamber volume instant regulating plunger extends out of the cylinder cover, and the lower end and the inner wall of the cylinder cover are in the same plane; a transmission mechanism connected with6 the combustion chamber volume regulating plunger is arranged at the upper end thereof, and the transmission mechanism is electrically connected with an electronic controller of an engine. The homogeneous compression ignition engine and the control system thereof drive the combustion chamber volume instant regulating plunger above the combustion chamber through the transmission mechanism, the combustion chamber volume instant regulating plunger enters the combustion chamber to change the volume of the combustion chamber; the aim of compression ignition can be still realized by the engine under various rotational speeds.