Laser quench and carbon alloying of 40Cr steel (Chinese brand)is performed on the surface. Carbon alloying is accomplished with pre-deposited carbon layer on the surface and scanning with the laser afterwards. The microstructure, micro-hardness as well as the wear properties were tested and compared with those obtained from the ordinary quenched work piece. It shows that: (a) the wear resistance of the laser quenched pieces is always superior than that obtained with ordinary quenched work piece; (b) after the carbon alloying, a thin layer of white iron was obtained which is very hard, but due to the presence of the residual austenite between the white iron layer and substrate, the wear properties of white iron layer is weakened.