The method which can simulate the stochastic process of the overload during the course of a projectile launching is discussed in detail. The calculated theory bases on the principle of information diffusion in fuzzy theory. To approach the actual launching overload, the calculated theoretical overload is disposed by the white noise. The dynamic test is used to calculate the fuze response of the launching overload. Finally, the launching overload of a projectile fuze is simulated to verify the validity of the method. The result is found basically to be in accord with the actual launching overload of the fuze, and the calculation accuracy is perfect.