Provided is a controller of an illumination system in an optical engine, in which a rear end of a light tunnel is fixed to a barrel and a front end of the light tunnel is movably installed inside the barrel, comprising: control openings being respectively bored through an upper part of the barrel; control screws being respectively connected to the control openings and moving the light tunnel in an oblique direction, each control screw with an end being obliquely in contact with the light tunnel; and an elastic body being installed in the barrel, opposite to the control screws, to elastically support the light tunnel. The controller of the illumination system controls the light tunnel to be moved in the oblique direction in the barrel, thereby enabling the light tunnel to be quickly and easily moved to be controlled, improving the controllability and shortening the control time.