A surgical robot system includes a slave unit and a computing unit (10). The slave unit includes a robotic arm (2), a surgical instrument (3), a cannula (9) and a sensing element (903). The robotic arm (2) is configured to drive the surgical instrument (3) to rotate about a remote center of motion (RCM). The cannula (9) is detachably coupled to a terminal of the robotic arm (2) and defines an axis passing through the RCM. The surgical instrument (3) is detachably connected with the terminal of the robotic arm (2) and extends distally through the cannula (9), and the sensing element (903) is disposed on the cannula (9) and configured to sense an axial deformation of the cannula (9). The computing unit (10) is configured to determine a radial force acting on the terminal of the surgical instrument (3), from a force on the cannula (9) sensed by the sensing element (903), according to the principle of torque balance. This surgical robot system has force feedback capabilities and obtains the radial force acting on the terminal of the surgical instrument (3) directly from a measurement with higher accuracy and not requiring any additional component, providing for reduced structural complexity of the surgical instrument (3).
