The remote haptic collaboration system between operating and assistant surgeons causes both shift and step delays of force feedback, and then makes users feel coarse reaction forces and different hardness of the object. In this study, we propose a haptic interface protocol for finite-element-method based deformable objects, in order to achieve a high update rate of force calculation. The method exports the necessary information for calculation of reaction forces from the simulation loop to the haptic loop. The experimental results indicated that the proposed method improved the fineness of force feedback and subjective hardness significantly.