The invention provides a fault seismic interpretation method for an intrusive rock development area. Firstly intrusive rock seismic calibration and interpretation are performed: then the seismic facies mutation points of the intrusive rock are identified, and the mutation points can be identified if one of the three conditions is met: the amplitude variation of adjacent seismic tracks is more than5%, the main frequency variation of the adjacent seismic tracks is more than 15% and the variation of the coaxial inclination angle is more than 20% on both sides of a certain track; and finally fault interpretation is performed, and the fault strike is interpreted in combination with regional tectonic stress field identification and fault development law. The great seismic reflection phenomenonof the intrusive rock is directly utilized to help identify the fault so that using the low signal-to-noise ratio data of the surrounding rock to interpret the faults in the past can be aovided and the interpretation scheme is more reliable. The breakpoint location determined by the seismic facies mutation points is more accurate and the fault interpretation accuracy is improved.