The micro-movement screw subassembly for linear displacement is assembled by screws and screw nuts, and the movement for lead and gear is combined together. However, a gap error always exists between the screw and screw nut, which is caused by error in machine processing for triangular thread surfaces and axial face as well as screw pitch deviation. Generally, when the error is more than 10 μm, it causes inaccurate screw leading linear displacement. Conventionally, the first solution is to use organic powder during the processing, and the second solution is to open an elastic groove on the screw shaft to reduce the gap error between the screw and the screw nut. The first solution is not easy and convenient, as the powder used to fill in the gap continuously falls out and needs to be replenished during work. The second solution does not work well either, while gap is reduced but the leading accuracy is still not good.