Abstract: Nine kinds of SPA-H weathering resistant steels containing different contents of Cu,Si and Ni were rolled in the laboratory by orthogonal experiment design of three factors and three levels,and the effects of alloy elements on microstructure,inclusion and low-temperature impact toughness of the tested steels were studied,as well as the effect mechanism of alloy elements on low-temperature impact toughness.The results show that the inclusion in the tested steels are all brittle inclusion Al2O3.Alloy elements had little effects on grain size and pearlite content,but had obvious effects on low-temperature impact toughness,and the effect order from larger to small is Si,Ni and Cu.The changes of impact toughness of the tested steels results from the joint effect of microstructure and inclusion.