A semi-automatic set screw assembling machine comprises a screwing-in device, a support, a screw guiding device, a base plate and a working platform, wherein the support is fixed on one side of the base plate, the working platform is arranged on the upper surface of the base plate, the screw guiding device and the screwing-in device are vertically arranged above the working platform in sequence and respectively connected with the support, the screw guiding device comprises a supporting plate and a guiding sleeve, the upper end of the guiding sleeve is in a cone shape, one end of the supporting plate is fixed on the support through bolts, a cone-shaped hole is formed in the other end of the supporting plate, the guiding sleeve penetrates through the cone-shaped hole and is fixed on the supporting plate, a screwing tool of the screwing-in device, the guiding sleeve and a threaded hole of a piece to be fixed are coaxial, movable inclined plane blocks are arranged on two sides of the working platform, a first limiting wedge and a second limiting wedge are installed between the inclined plane blocks, and the first limiting wedge and the second limiting wedge are in linkage. The semi-automatic set screw assembling machine has certain flexibility, the phenomenon of destroying a screw hole or a screw by screwing is avoided, clamping and uninstalling are synchronous, a screwing length of threads can be adjusted, operation is easy and convenient, production efficiency is high, and an application range is wide.