Abstract: In order to achieve a better blasting effect,the selection of the position of the hole in the front row and the depth of the perforation are of great importance.According to the different forms of free surface and different lithology of the open pit slope,it is very important to determine the blasting parameters suitable for the geological status quo in the northern part of Shijiaying.In the following three forms of free surface: slope,facade,backslope and fixed slope angle,how to set reasonable blasting parameters under the same lithology,to ensure better blasting effect in the subsequent blasting construction.The analysis results can provide reference for future blasting.

Key words: Free surface, Blasting parameters, Blasting effect, Slope angle