The invention relates to a welding method of a deflation valve. The welding method comprises the steps that a crank and a valve cover shaft are cleaned; the crank and the valve cover shaft are clamped, and an annular gap exists between the crank and the valve cover shaft; a CCD is moved to the first preset position corresponding to the deflation valve; the CCD shoots the deflation valve, and data information of the circle center coordinates of the end face of the valve cover shaft are output; according to the data information, a laser welding head is moved to a second preset position, and the projection position of the second preset position on the deflation valve is located on the side, away from the circle center coordinates, of the annular gap; and the laser welding head conducts welding sequentially along the arcing path, the welding path and the arc retreating path. In the welding process of the welding method of the deflation valve, starting from the second preset position, moving is conducted along the arcing path, the welding path and the arc retreating path, overlapping of the welding path is avoided through control over the welding path, and the phenomena that the depth at the arcing position is not enough and solidification hot cracks are likely to be generated at the bonding position can be effectively eliminated.