The invention provides a single-shaft spiral feed mechanism based on a differential motion principle. The single-shaft spiral feed mechanism comprises a spiral feed mechanism body, the spiral feed mechanism body comprises a screw rod, the screw rod input segment is installed to an inner main shaft through a first bearing set, the inner main shaft is installed inside an outer main shaft through a second bearing set, the end face of the outer main shaft is provided with a poking fork set, the poking fork set is in small clearance fit with a feed main shaft, an inner ring of the feed main shaft is fixedly connected with a screw rod nut on the screw rod, the screw rod is coaxially and fixedly connected with a first motor main shaft, the outer main shaft is provided with a big belt wheel, the big belt wheel is connected with a small belt wheel through a synchronous belt, and the small belt wheel is coaxially and fixedly connected with a second motor main shaft. According to the single-shaftspiral feed mechanism based on the differential motion principle, by means of differential motion rotating of the inner main shaft and the outer main shaft driven by a first motor and a second motorcorrespondingly, spiral feed of the feed main shaft is realized, and by means of double-motor rotating speed distribution, adjustment of the rotating speed and the axial feed speed can be realized, and the single-shaft spiral feed mechanism based on the differential motion principle is simple and effective.