Objective:To find valid indicator to differentiate random test of MMPI-2.Methods:According to four coincidence indicators of MMPI-2 of 1278 psychiatric cases (male, 623; female,555), including VRIN,│F-Fb│,VRIN+│F-Fb│,F+Fb+│F-Fb│,differentiate random test of MMPI-2 were studied.Results:VRIN+-F-Fb-,-F-Fb-were the best indexes. VRIN was a fine index. F+Fb+ and│F-Fb│were poor.Conclusions:It is not good to use one coincidence indicator, but it can eliminate 91.50% of random test if the four coincidence indicators are used together.