A simple model of laser induced bubble collapse is proposed.When the initial phase is determined the values of thermal diffusion and mass diffusion of the bubble are considered and subtracted,and so the mass of water vapor remains uniform through the whole collapse process.The compression of water around the bubble is also considered.The bubble radius of 1mm is investigated.The maximum collapsing velocity is 1172.8 m/s,the maximum pressure in bubble center is 8.8728×108 Pa,and the minimum radius is 15 μm.The model is simple and practical,and the initial conditions of the bubble can be used in the research of the interaction between the elastoplasticity solid wall and the laser induced bubble.