The invention relates to a nonmetallic composite deoxidizer and a steel-making deoxidation method applying the composite deoxidizer. The nonmetallic composite deoxidizer contains SiC and CaC2, wherein the content of the SiC is between 25 and 40 weight percent, and the content of the CaC2 is between 60 and 75 weight percent by taking the total weight of the deoxidizer as the reference. The composite deoxidizer is a low-cost and high-efficiency steel-making nonmetallic composite deoxidation material, and can effectively remove free oxygen in molten steel and reduce the oxidability index of ladle slag. By utilization of the deoxidizer to replace aluminum alloy in the prior art for steel-making deoxidation, utilization of a large quantity of expensive aluminum alloy during deoxidation of the molten steel can be avoided; and because the nonmetallic composite deoxidation material does not have the phenomena of floatation and slag wrapping, the deoxidation effect is good. Compared with the prior deoxidizer, the composite deoxidizer can improve the yield of common alloy elements, namely Si and Mn, by 5 to 8 percent when used for deoxidation.