Abstract: Liquid film solution diffusion wleding is applied to joint of iron and steel materials,and the effects of spray melt temperature that represented by liquid film state on interface microstructure and properties have been studied.The results show that with increasing of the spray melt emperature,on one hand,the interface diffusion layer thickness and the tendency of forming hardening phase in matrix near the interface increase,on the other hand,the joint strength and hardness increase.In the hardness distribution the peak hardness in welding zone is located in the hot-affected zone near the interface.Keeping the static mirror surface of liquid film state(700℃~800℃)contributes to obtain the good welding zone in which there is no chill and hardening structures.