A lot of width data surface rupture zone of Wenchuan M8.0 earthquake and other historical earthquakes occurred on the thrust fault are comprehensively analyzed. We calculated that the effective width of thrust faults "avoiding belt" is about 30 m by statistical analysis methods, and obtained that the width of "avoiding belt" of hanging wall of active fault is about 20 -22.5 m, and its foot wall is about 7.5 - 10 m. The research results can provide references for construction engineering for avoiding thrusting fault and other fault types.