Abstract: This paper proposes the Operator-splitting (OS) method for dynamic substructure testing, and investigates the stability and effectiveness of the method. The main conclusions are as follows. 1) This paper proposes a target acceleration formulation so as to render the OS method an explicit formula for dynamic substructure testing. 2) It is shown from spectra analyses and numerical simulations that for the case of inertial specimen, this method is conditionally stable as long as the mass ratio of the experimental substructure to the numerical substructure is less than or equal to 1, while it is a unstable method if the ratio is large than 1.