A multi-channel stepped motor operated gas adjusting valve comprising a gear motor and a valve shell, the valve shell being provided with a gas inlet and at least one gas outlet, the gear motor being mounted on an outside wall of the valve shell, a driving shaft of the gear motor being inserted in the valve shell and sealingly connecting with the wall, characterized in that, there are N gas outlets provided on another wall of the valve shell perpendicular to the driving shaft, and N is an integer selected from the group consisting of 2∼5; a cylindrical locator is positioned on the driving shaft; a plurality of locating points are disposed on an outer circumference of the locator, a round gas distributor is disposed to be slidably connected with the locator via splines, and center lines of the gas distributor, the locator and the driving shaft are vertically aligned; a gas outlet O-ring and a hard hollow washer are positioned respectively in sequence from outside to inside at an inner port of each gas outlet, and an inner end face of the hard hollow washer is slightly higher than that of the gas outlet; N groups of gas distribution grooves and corresponding N gas distribution start holes are disposed in a gas distributor disk which is perpendicular to the center line of the gas distributor and has a center located in the center line of the gas distributor; each of the gas distribution grooves is rectangular and has a plurality of through holes each of which independently has a sectional area of 0-20 mm 2; all center lines of the gas distribution grooves pass through the center of the gas distributor disk; an angle included between adjacent center lines of two adjacent gas distribution grooves in each of the N groups is the same; the gas distribution start hole coincides with the corresponding gas outlet; and an angle included between a line connecting a center of each gas distribution start hole with the center of the gas distributor disk and the center line of the gas distribution groove adjacent to the gas distribution start hole is the same; the multi-channel stepped motor operated gas adjusting valve also comprises movable sealing devices, and each of the movable sealing devices is located at the corresponding gas outlet and comprises the inner port of the gas outlet and the corresponding gas distribution start hole; a pressure spring is disposed between the locator and the gas distributor, such that the gas distributor disk abuts against the hard hollow washer; a locating portion corresponding to the group of locating points is disposed on an inner wall of the valve shell; the locating portion and the group of the locating points form a locator rotation angle detecting mechanism, and one to one correspondence is provided between each of the locating points and the corresponding each of the gas distribution grooves; and stopping blocks are disposed on the inner wall of the valve shell corresponding to a start state and an end state of the locator, respectively, wherein the movable sealing device consists of the inner port of the gas outlet, the gas outlet O-ring and the hard hollow washer disposed in the inner port, the gas distribution start hole and a semi-enclosed cylinder extending backwards from the gas distribution starting hole, as well as a sealing spring and a rigid ball installed in the semi-enclosed cylinder; the rigid ball has a diameter slightly larger than an inner diameter of the gas outlet O-ring and slightly smaller than an inner diameter of the hard hollow washer, and the rigid ball and the inner wall of the semi-enclosed cylinder slide fit each other.