The invention discloses a combustor of a gas machine. The combustor is arranged at the head of a piston and comprises a bottom surface and a plurality of diversion edges evenly arranged in the circumferential direction of the head of the piston. Each diversion edge comprises a vertical wall bending inwards and an inclined wall, wherein the vertical wall is provided with a bottom tip end and a top tip end; the bottom tip end and the top tip end are arranged on the bottom surface and the top surface of the head of the piston respectively; the bottom tip end bends towards the center of the combustor; the side wall of the combustor is formed on the inner surface of the vertical wall; the bottom end of the inclined wall is connected with the bottom surface; the upper end of the inclined wall extends to the top surface of the head of the piston; the inner side edge of the inclined wall and the front section part of the upper side edge of the vertical wall are connected so as to form a convex edge protruding inwards; the convex edge extends from the bottom tip end to the top surface of the head of the piston; the outer side edge of the inclined wall is connected with the rear section part of the lower side edge of the adjacent vertical wall. By means of the combustor, reasonable airflow motion can be organized, and the combusting turbulence intensity and the spreading speed of combusting flame are optimized.