Abstract: In soft tissue modeling,accuracy and real-time performance are two contradictory requirements.In this paper,we investigate an efficient physical modeling method for real-time simulation of human liver.To this end,volume spring is first introduced to simulate the volume behavior of liver based on a surface model of the mass-spring system.Volume discretization is then used to determine the mass of the mass points.Based on hierarchical bounding,a gravity correction method is also proposed to ensure the accuracy of the mass distribution.To determine the parameters of the springs used in the model,a piecewise linearization method is proposed based on biomechanics experiments on real soft tissue and parameter analysis.Stress analysis and optimization have also been conducted to improve the efficiency of deformation simulation.Experimental results show that the proposed methods perform well in simulating the deformation of soft tissues and also help to improve the real-time property of the simulation.