Fe-Cr-C-B-Ti-B,4,C wear resistant surfacing layer is prepared on Q235 substrate by automatic CO,2, gas shielded welding.Microstructure and performance of the surfacing layer are studied by metallographic microscope,X ray diffractometer,hardness tester and abrasive wear machine. The results show that addition of B,4,C has significant effect on the variety,morphology and quantity of the microstructure,which further affects the hardness and wear resistance of the surfacing layer. The microstructure of surfacing layer without B,4,C is composed of needle-type martensite,retained austenite and eutectic structure;and after adding B,4,C,the microstructure of surfacing layer is cellular primary austenite and eutectic structure. With the increase of B,4,C content,the hardness of the surfacing layer improves gradually,while its wear loss increases firstly and then decreased. When the content of B,4,C is 20%,the wear resistance of the surfacing layer is the best.