CO2 laser beam butt welding the bimetal saw made of 50CrNiMoVA high-strength alloy steel and W2Mo9Cr4VCo8 high-speed steel has been completed. The influence of side-play amount between laser beam and weld on weld shaping has been discussed. Weld microstructure, micro-hardness and toughness are analyzed through metallurgical test, micro-hardness test and bending test, meanwhile the influence of heat treatment on weld microstructure, hardness and bending property are discussed. The welds without transition layer which are smooth and no external defects, can be obtained. After 1190 ℃ marquenching and three times 560 ℃ tempering for 2 hours, the bimetal saw has no crack in 90° bending test and its property has achieved to industry level.