Considering liquid slight compressibility, the dynamical behaviors of a bubble cluster in an acoustic field are investigated by regarding water as a work medium. The effects of initial radius of gas bubble, the number of bubbles for monodisperse cluster and polysidperse cluster, acoustic frequency, acoustic pressure on bubble dynamics are numerically simulated. The effect of each parameter on bubble motion state and collapse pressure is analysed. Chaotic characteristics of bubble dynamics in monodisperse cluster are investigated. Two collapse pressure features under chaotic state are analysed. The results show that the suitable parameters are helpful for improving cavitation treatment effect.