In this paper,the percolation of rock fracture is studied by using computer simulation method,and when micro-fractures distribute randomly,fracture cluster distribution pattern,fracture cluster size distribution law,total fracture cluster number, cluster mean size,b value,percolation fractal dimension D,critical case and so on are given. The results according with other models and laboratory experiments show that the percolation mode is a suitable model for describing rock fracture process. Two turning points in rock fracture process are found,thus authors point out that studying macroscopic character of rock nearby those two turning points can better research precursory character in seismogenic process.