The invention discloses a complex deoxidizer for steelmaking, which comprises the following components in percentage by weight: 5 to 9 percent of calcium (Ca), 10 to 24 percent of silicon (Si), 12 to 19 percent of manganese (Mn) and the balance of Fe, accompanying elements of Al and Mg, and inevitable impurities. The invention also discloses a method for preparing the complex deoxidizer for steelmaking, and the complex deoxidizer is prepared from the following raw materials in proportion (in percentage by weight): 60 to 70 percent of raw manganese ore in which Mn accounts for more than or equal to 32 percent, 12 to 16 percent of silica with the silicon content more than or equal to 98 percent, 10 to 16 percent of lime with the CaO content more than or equal to 90 percent and 5 to 8 percent of iron scale with Fe oxide content more than or equal to 75 percent. The complex deoxidizer and the preparation method have the advantages of low cost of the raw materials, low energy consumption of unit product, reasonable proportion of alloying elements, no segregation, strong substitution and high strength of product, high density and low smelting point of alloy, easy absorption for alloyingelements in molten steel, good deoxidation, desulfurization and dephosphorization effects, and high metal yield.