The research and manufacture of endless diamond wire saws have been reported in this paper. The matrix of saws was 65Mn steel wire whose diameter was o.8mm, and was welded as a ring by argon arc welding. The endless diamond wire saws were made by setting diamond abrasives on endless steel matrixes using nickel-plating method. The cutting experiments were carried out using the diamond wire saws on the homemade test equipment. The characteristics of the saws are narrow slot, high cutting speed, low noises and good surface quality. The surface cut could be finishing grinding or polishing directly, so the productivity could be improved greatly. Endless diamond wire saws can cut not only rock, but also valuable hard and brittle materials such as ceramic, boulder, and silicon etc.