The invention discloses a sectional type three-channel fuel gas plug valve. The sectional type three-channel fuel gas plug valve comprises a valve body and a hollow valve core which is rotationally mounted in the valve body. The interior of the valve core is a gas distributing cavity and the axial end part of the gas distributing cavity communicates with an air inlet hole on the valve body. Three groups of gas supplying holes, which are corresponding to continuous firepower, inner ring firepower and outer ring firepower separately, are distributed on the side wall of the valve core along the axial direction and three groups of air outlet holes, which are corresponding to the three groups of gas supplying holes, are formed in the valve body. The gas supplying holes in the identical group are distributed on the side wall of the valve core along the circumferential direction; one of the gas supplying holes in the identical group is a master gas supplying hole and a through hole, and the other gas supplying holes in the identical group are slave gas supplying holes and blind holes arranged on the outer wall of the valve core; each two adjacent gas supplying holes in the identical group communicates with each other directly or through a channel which is arranged on the side wall of the valve core. According to the fuel gas plug valve, multiple sections of firepower can be set and a user can find the desired firepower according to the cooking requirements; and the firepower is uniform in variation without firepower sudden change sense when switched between sections.