A composite inhibitor of stainless steel in acidic potassium permanganate decontamination was prepared by orthogonal method. Its property of inhibiting corrosion was evaluated by weight-loss method, electrochemical test and surface analysis. The results show that the compound inhibitor is a kind of cathode type inhibitor. It is well used in normal temperature and inhibition efficiency reach 97.40%.It is very little that high-speed flow of liquor impact on restraining the ability of matrix corrosion. The photos of metallurgical microscope and electron probe indicates that signal of heterogeneous corrosion is not found under different corrosion condition.