The work aims to study the distribution of residual stress of plasma cladding of Co-based alloy under different process parameters and select the optimal combination of process parameter to reduce the residual stress. Orthogonal experiment was designed and nine groups of single channel Co-based plasma cladding samples with different process parameters were pre-pared by plasma cladding. Blind-hole method was used to measure the residual stress at the starting location, intermediate location and finish location of each sample, and the influence of working current, scanning speed and powder feeding rate on the residual stress was analyzed. The residual stress on the surface of the samples was mainly tensile stress, and the residual stress at middle location was the maximum. The residual stress parallel to the scanning path was greater than that perpendicular to the scanning path. When the working current was 92 A, the scanning speed was 100 mm/min, and the powder feeding rate was 12 r/min, the residual stress of the formed sample was the minimum. The working current has the most significant impact on the residual stress of the starting location and the finish location parallel to scanning path and other locations in all directions. The most significant factor is the scanning speed. The greater the working current is, the greater the residual stress is. With the increase of the scanning speed, the residual stress becomes smaller. With the increase of the powder feeding rate, the residual stress has an increasing trend. The residual stress can be effectively controlled by selecting the proper combination of process parameters.