Abstract: To study the characteristics of the pyrotechnic shock environment concerning a pyroshock separation nut, the mechanism of the pyroshock load, and the process of the stress wave propagation in the structural materials, the dynamic shock process of the pyroshock separation nut is simulated by using the LS-DYNA non-linear FEA software, and the acceleration response and the load curve at typical positions, and the load curve of the interface of the satellite and the launch vehicle are obtained by an integrative simulation of the pyroshock separation nut and the structure. The results provide a more exact input condition for the protection design of the spacecraft pyrotechnic environment.