An adaptively deformable model for web-based virtual surgery is proposed. In this model, external forces propagate on layer-by-layer basis into soft tissues and thereby leading to changes in shape. By controlling the penetration depth of external forces, deformation is restricted to occur only in localized regions, and optimization between computational complexity and accuracy is achieved. This technique avoids laborious formulation of stiffness matrix in conventional mass-spring models. Experimental result show that the model is suitable for modeling materials of various mechanical properties.It can also be used for multi-user collaborative work in virtual enbironments and integrated with multiple degree-of-freedom haptic devices.