Abstract: After adjusting components of the Fe-Cr-Ni alloy powder whichis used to laser clad on 45 steel,we find that the expansion coefficient of clad layer and it's cracking sensitivity have been changed,and the cracking sensitivity decrease with lowering of expansion coefficient of clad layer.In this paper we discusse these results and point out that proper selecting the range of the difference of expansion coefficient between clad layer and substrate is beneficial to reduce cracking sensitivity of clad layer.