The invention relates to a lightweight drive shaft with minimum parts. The lightweight drive shaft comprises a front drive shaft and a rear drive shaft. A second spline shaft is welded at one end of the front drive shaft, a welding yoke is welded at the other end of the rear drive shaft, and the second spline shaft and the welding yoke are arranged opposite to each other; the welding yoke is provided with a sliding yoke into which the second spline shaft is inserted; and the second spline shaft is provided with a locating sleeve and a snap spring, wherein the locating sleeve fixes a bearing on the second spline shaft and is clamped and limited by the snap spring to be fixed, and the locating sleeve and the snap spring are located at the side of the sliding yoke. By using a design of minimum parts and light weight, the lightweight drive shaft with minimum parts changes the structure of spline shafts in the middle and thus endows the spline shafts in the middle with a function of fitting an intermediate support with slide splines, the number of parts is reduced, and the fitting accuracy and reliability of the driving shaft are improved.