The invention provides a machining process of a double-metal band saw. A saw back material and a saw tooth material are welded by laser; then, the bright annealing treatment is performed; a two-roller rolling mill is used for welding line leveling, straightening, repeated extrusion and fixed-length material preparation to obtain a coiled band; then, the tooth milling, the tooth material cleaning, the tooth separation, the quenching treatment and the subzero treatment are performed; and the rolling straightening, the sand blasting, the code spraying and the root band butt welding are performed after secondary tempering treatment to obtain the double-metal band saw. Compared with the prior art, the machining process uses carbon, silicon, manganese, chromium, tungsten, molybdenum, vanadium, nickel, cobalt, niobium, sulfur and iron as components of the saw tooth material, and improves the hardness and the toughness of the double-metal band saw through adjusting the contents of all the components. Secondly, the machining process adopts such modes as quenching treatment and subzero treatment to guarantee the tempering sufficient degree, and improves the characteristics of high hardness, high toughness and tidy incision of the double-metal band saw.