Abstract: Using three dimensional fast lagrangian method,this paper numerically simulated the cavern excavating in different conditions of workplane distance,Poisson ratio,cover depth and aspect ratio based on three dimensional numerical model,for searching the rule of how the above factors influencing the diplacement release coefficient of the top arc and side wall of cavern.The numerical simulation method is rapidly and highly active,it is cheaper than in-situ experiment.The researching conclusion could supervise to accurately analyze the moitoring dada in cavern construction period.