The influence of carburizer in salt bath which contains some rare earth elements on the technical paramenter of heat treatment and the property of hand saws with low carbon steel are investigated. The compositional recipe of carburizer and the technical parameter of heat treatment are determined by means of the microstructrue analysis,peeling analysis. TEM observation and sawability test. The effect of rare earth elcments in chemical heat treatment of salt bath and its influence on microstructure and properties of hand saws are also discussed.