Abstract: For the large-area deep hole blasting occurred in open pit mine with heterogeneous rock mass，the optimized blasting network is designed to determine the action direction of blasting.Then，good blasting effect on the heterogeneous rock mass with various structural planes can be achieved.According to the development trend of the joints and fissures in the heterogeneous rock mass，the blasting action line increase the radial tensile stress by increasing the radial tensile stress through the hole-by-hole millisecond free surface blasting.Based on the analysis of the lithology and structural plane of 3# mining area in Heishan coal mine，the theory of lasting action line is pointed out: for rocks with complex structure，blocky rocks can be lowered by increasing the free surface blasting，designing the symmetrical V type oblique interval blasting action line of nonel detonation network to realize the hole-by-hole millisecond blasting.For the heterogeneous rocks existing in some place，uniform rock breaking can be realized by determining the blasting acting line to strengthen the blasting effect，designing the oblique interval blasting action line of nonel detonation network to realize the hole-by-hole millisecond.These research results can provide some reference to resolve the problem of blasting technology for heterogeneous rocks in arid area in open pit coal mine.

Key words: Blasting action line, Heterogeneous rock mass, Breaking effect