A ball screw capable of sensing a torque in real time includes a screw rod, a screw nut sleeved onto the screw rod, a plurality of balls mounted between the screw rod and the screw nut, and a torque sensor haying a first fastening portion and a second fastening portion. The first fastening portion is fixed to a working bench and the second fastening portion is fixed to the screw nut, so the torque sensor can sense how much the torque is while the screw out is driving a working bench to move. In light of this structure, monitoring the voltage value outputted by the torque sensor can sense the torque generated while the working screw rod is working.