In order to identify the inertia parameters of complex structure rigid body with high efficiency and accuracy, an identification test device was built based on the FRF mass line method. The influence of system stiffness and damping, noise, coordinate error of excitation point and response point, angle error of hammer excitation and sensor installation on the identification accuracy were obtained by multibody dynamics simulation. A rigid body with known inertia parameters was identified by the proposed device and the error was within 5%. It shows that the test device based on the FRF mass line method can identify inertial parameters of complex structure rigid body efficiently and accurately.