When nano-abrasives of high speed polish work-piece, they cut it and crush it and there are brittle fracture and surface distortion. For work-pieces of hard-brittle materials, there should be no surface distortion. Therefore, the efficiency of nano-abrasives polishing work-pieces of brittle materials should be much lower than that of metals. In this paper, work-pieces of Cr12MoV and glass K9 are polished by nano-abrasives driven by high speed hydrodynamic suspension fluid to study how it works. The experiments show that the efficiency of nano-abrasives polishing work-pieces of hard-brittle materials is much higher than that of metals.