The impact force of micro-detonation of striking arc machining is studied. The orthogonal experimental design and regression analysis method are employed to build the prediction model and the influencing laws of processing parameters on impact force are educed. Experimental results show that the impact force decreases with the increment of working current and increases with the growth of working pressure and nozzle diameter. The exponential type model is consistent with experiment results. The research can offer an important reference for the process control of micro-detonation of striking arc machining.