Vibration compaction is used as a way to improve the capacity of rubble bed. By vibration, small particles are made into pore to increase the compactness of medium. Then, the bearing capacity can be improved. Vibration compaction must select reasonable parameters, such as vibration times and the vibration hammer mass. But because of the lack of theoretical basis, how to select reasonable parameters became a problem. Based on the size of random rubble in site, PFC2D is adopted to establish the model, and effect of vibration process, vibration times and vibration hammer mass are discussed. It concludes that when vibration hammer mass is 8t and the vibrating times is 6 times, the compaction effect is most obvious. The research findings can provide reference to vibration compaction.