Using forcelimited technology can ease overtesting which caused by the difference of impedance of the interface between satellite and rocket.Semiempirical method is a significant technology to acquire interface force.It is critical to identify the parameter of semiempirical.This paper,based on fixed interface substructure modal synthesis method,deduce the theory expression of semiempirical coefficient and analyze the relationship of the parameter between semiempirical and satellitespacecraft systems.Using the method,we calculate semiempirical coefficient of a certain engineer satellite model and formulate sine testing forcelimited condition,and verified by testing data.Experimental results indicate that the force limited condition, acquiring from this method,can preferably reflect the real stress between the satelliterocket coupling system in resonance peak.It can provide some reference for the engineering application of the semiempirical method.