An orthopedic surgery assistant system includes: a multi-axis mechanical arm module； at least one end effector, including: two linear actuating elements, two actuating element encoders, a central annular structure, a connector, and a power/torque sensing element； a guide and positioning module； and a surgery remote control module, so that a user pulls the multi-axis mechanical arm and the end effector according to a real-time three-dimensional model, so that the multi-axis mechanical arm performs translation and rotation motions in a plurality of axial directions on an applied end, and the end effector performs a rotation motion of two degrees of freedom on the applied end.
