Abstract: Due to the frequent blasting vibration in open pit mining, the slope failure mechanism and stability analysis are extremely complicated, which is a serious threat to safety production. This paper takes the mine excavation slope as the background, bases on engineering geological conditions and field test, uses the combination of theoretical analysis and mathematical calculation to quantify the blasting load, then establishes a slope blasting damage calculation model and determines the slope failure time and the most dangerous area. At the same time, verifies the accuracy of the calculation results by numerical simulation method. The results show that the upper step of the slope destroys after 7 times blasting, and the most dangerous area is located at the initial position of the blasting of 120m ~160m. The numerical simulation results are consistent with the calculation results, which fully verifies the accuracy of the method.