Abstract: In order to improve the precision and the real-time performance of simulating soft tissue deformation,a novel physically-based layered rhombus-chain-connected deformation model is proposed.The accumulation of relative displacements in every chain structure unit in every layer is equal to the object surface deformation in the model,and the resultant force of corresponding springs is equivalent to the external force.The haptic interactive system is built upon a hand controller of Delta 6-DOF,with which the interactive operations such as pressing and stretching the virtual soft tissue are carried out and the tactile sense is produced by the feedback force.The experimental results show that the proposed model has less calculation cost and can ensure higher precision in calculating the contact force and the deformation.Meanwhile,it can provide stable force and nature simulation effect to human operator and satisfy the requirement of real time-performance and accurate operation in our virtual reality system.