This paper analyzed the vibration transmission characteristic of a sheet structure with rigid blocking mass. The vibration-isolating performance of a hollow blocking mass was studied for comparison, then the vibration isolation technology of the sheet structure was developed. Based on a transmission characteristic analysis of the blocking mass using the wave approach, an experimental model for a sheet structure with approximately equal-mass hollow beams and solid beams was designed. By measuring the average vibration acceleration of the plate structures, the transmission losses of both types of blocking masses were obtained and comparatively studied. Moreover, the vibration-isolating performances of both types of masses were analyzed, and the effect on the vibration-isolating performance of the hollow blocking mass filled with damping particles was measured. The results show that the hollow blocking mass had a better vibration-isolating performance than did the solid blocking mass, and the effective vibration-isolating frequency moved to low frequency. The vibration-isolating performances of both arranged solid and hollow blocking masses were a little better than that of the single arranged blocking mass. Filling the hollow blocking mass with dam ping particles might further improve the vibration-isolating performance.