The invention discloses an adjustable flue gas uniform distribution device for an submerged combustion gasifier. The adjustable flue gas uniform distribution device comprises a flue gas uniform distributor, wherein the flue gas uniform distributor is composed of an inner flue gas uniform distributor pipe section, an outer flue gas uniform distributor pipe section and a dead zone turbulent flow section; two ends of the inner flue gas uniform distributor pipe section are connected with the dead zone turbulent flow section, one end of the inner flue gas uniform distributor pipe section is in a flange connection mode, and the other end of the inner flue gas uniform distributor pipe section is in a welding mode; and the inner flue gas uniform distributor pipe section is coaxially embedded intothe outer flue gas uniform distributor pipe section, and the outer flue gas uniform distributor pipe section is connected with the power output of an electric servo system actuating mechanism. According to the requirement of the gasification rate and the gasification amount, the electric servo system actuating mechanism A drives the outer flue gas uniform distributor pipe section to rotate to a corresponding angle to change the diameter of a flue gas spraying hole so as to adjust the effective flue gas spraying area, and therefore, the spraying speed of the flue gas is controlled in a certainrange, so that the flue gas fully exchanges heat with a water bath, the disturbance of a strong transverse pipe bundle is achieved, the freezing of a serpentine coil pipe is avoided, and the purpose of improving the gasification rate is achieved.