Abstract: In order to improve the effectiveness of anti-collision system in offshore cluster well drilling anti-collision prediction model of drill bit approaching adjacent well was built based on the theory of elastic waves in spherical spreading and absorption attenuation,and amplitude attenuation pattern analysis of actual measured data.Through adjacent well casing vibration monitoring and data processing,the distance between the drill bit and adjacent well casing can be calculated by using the model,and the chance of well collision can be identified and warning provided.The model was used to analyze the casing vibration signals of adjacent wells in Bohai Sea,and gave the distance between dill bit and adjacent well casing.The distance between drill bit and adjacent well casing calculated from the model and well distance from log data matched well.It demonstrated that the model can be used to predict the distance between drilling and adjacent well,which could provide a new technical support for safe drilling of offshore cluster wells.