Abstract: A semiempirical model of electro-explosive fuse opening switches (EFOS) based on the dependence of fuse resistance increase on specific energy is developed. The switch model coupled with the inductive energy storage system(IESS) is integrated into PSPICE circuit simulation code. The calculations of EFOS output pulses are in agreement with the experimental results . The relationship between the load resistance and output pulse is also discussed by means of the circuit simulation.