Abstract: The effect of Ca-Si wire feeding on oxygen content and inclusion in Al-deoxidized and vacuum degassed GCr15 steel was investigated by oxygen content analysis, inclusions rating and electron probe observation. The results show that there was no further effect on oxygen content and D-type inclusion between Al-deoxidized and vacuum degassed GCr15 steel with Ca-Si wire feeding after LF and VD secondary refining and Al-deoxidized GCr15 steel without Ca-Si wire feeding. The problem of nozzle clogging during continuous casting could be solved by feeding Ca-Si wire. Granular calcium-aluminates wrapped by a layer of calcium sulfide were formed in GCr15 steel treated by refining slag of CaO-SiO2-Al2O3.