Abstract：According to the fracture characteristics of rock under indenter，the relations between the length of the median，radial and lateral cracks and the loading parameters of impact hammer，impact speed and static pressure were determined. The cutting effects of rock influenced by impact frequency were also analyzed. On the multifunctional testing device，the indentation and cutting test under coupling dynamic and static loads were conducted on granite. Experimental results show that the cutting effects of rock can be improved greatly under the combined loads，the special energy consumption of rock fragmentation varies with the ratio of impact point space to cutting depth，and has an optimum value at which the cutting effects of rock are optimum. The reasonable method of fragmenting rock is that enough large crack area is caused firstly by impact load and then rock is cut by cutting load and static load. High energy，high frequency and small impact space have good effect on cutting the brittle hard rock.
