By means of cutting marble plate by the post mixed abrasive jet with additives PAM and measuring the kerf width and the cutting surface roughness, explores the effect of drag reducer on the jet cutting quality. The experiment result indicates that the drag reducer has contracting effect on jet beams, the kerf of the abrasive jet with drag reducer is narrower than that of common abrasive jet under the same conditions, and the jet with the drag reducer can reduce the roughness of cutting surface and improve the cutting quality. In the test, the cutting quality is improved with the increasing of drag reducer mass fraction.