Abstract: A friction reduction tool for rotating drill strings during slide drilling, namely the rotary slide drilling (RSD) tool, was developed to address the technical problems of high friction and a low rate of penetration (ROP) in slide drilling. A bottomhole assembly (BHA) torsional dynamic model was built to analyze the effects of the torque and position of the RSD tool on the toolface azimuth of the screwdrill. The prototype RSD tool was tested indoors with a test device that could simulate the antitorsional vibration of the screw. It was also tested in the test wells. The theoretical analysis and test results show that the RSD tool has a feasible working principle and a reasonable structural design, and it can stabilize and adjust the toolface azimuth of the screwdrill while rotating the drill string. Rresearch indicates that the RSD tool can not only realize the slide drilling of the screwdrill but also reduce friction by rotating the part of the drill string above it.