The output of piezoelectric impact sensors used in piezoelectric fuse is influenced by the shock orientation, a quantitative analysis method of sensors orientation effect is proposed. Based on the working principle of piezoelectric sensors, a mathematical model of piezoelectric impact accelerometer’s orientation output is constructed. Using this model, quantitative analysis of orientation effect on impact sensors is studied, and the directional response laws of piezoelectric sensors is obtained, the best impact orientation can be calculated. It’s shown from the simulation experiment that the multi direction sensors are superior to single direction sensors, and orientation effect is related to the ratio of direction sensitivities, this evaluation method provides a theoretical basis for the development of piezoelectric fuse.