Abstract: Based on the fundamental theories of numerical manifold method (NMM), a criterion of crack initiation and crack growth is introduced into NMM. NMM is used to numerically study the process of two-hole blasting, in which two different initiation conditions are considered. One is simultaneous initiation, the other is 0.1 ms delay initiation. The whole blasting process including crack initiation, crack growth, the formation of fragments and the formation of a blasting crater is simulated. The failure mechanisms of rock under blasting loading and the influences of initiation conditions on that process are analyzed. NMM has proven to be an effective and accurate method for in the study of rock failure from a continuous mass to a discontinuous mass. The results provide further insights and a new method in the research of the related issues.