Abstract: The force balance of the soft tissue should be computed in the celiac minimally invasive surgery to get the graphic feedback of the soft tissue deformation.The geometrical model of gallbladder and its accessory ducts upon which the spring-mass mechanical model is bestowed is established,and a force balance algorithm based on successive approximation is presented to compute the soft tissue force balance.The algorithm is easy to implement,the programming workload is small,and the real-time performance is good.The simulating result shows that the algorithm can generate relatively factual graphic feedback of the soft tissue and can be used in soft tissue simulation.