In order to solve the problem that the singlelevel drive system is difficult to realize the largestroke and ultraprecision positioning at the same time,an ultraprecision largestroke feeding experimental platform based on ball screw and hydrostatic guide rail was designed.The frameless direct drive motor was directly connected with the ball screw through the expansion sleeve,and “zero transmission” similar to the linear motor was achieved.The displacements of the moving parts were detected in real time by using the nanometer resolution grating ruler.Experimental results show that the positioning performance of the system can be improved by means of G code compensation,friction compensation,increasing PWM frequency and reducing interference.The feeding system can achieve the positioning accuracy of 103 nm and the motion resolution of 8 nm in an effective stroke of 180 mm.