This paper presents a numerical method capable of analyzing vibration problems of a plate, which has damped one-degree-of-freedom absorber systems. Lagrange's equations of motion will be employed based on the kinematic, strain and dispersive energies for the plate and damped absorber systems. The deformation of the plate will be approximated as a continuous system by using. Ritz method. The present authors will also carry out the experimental work in order to study the interactive effects between the plate and mass-spring systems, and also verify the validity of the proposed numerical method. The vibration of deck loaded with cars in pure car carrier will be considered as a typical example of interactive vibration of plate and mass-spring systems. By applying the proposed numerical method, the present author will investigate characteristics of vibration of car deck in the steady state, and transitional behaviors of deck during the slamming.