28MnCr5 is a kind of advanced gear steel. Its internal quality is closely related with its solidification structure. During the production process of continuous casting, the relationship between solidification structure and actual parameters has been investigated. At the same time, according to the actual casting process smelting 28MnCr5 parameters, using ProCAST software and CAFE model to simulate the solidification.The results show that when the superheat increases from 10℃ to 40℃, the grain density increases from 6.911×106m-2 reduced to 4.133×106m-2, the average grain surface area increases from 1.447×10-7m2 to 2.419×10-7m2, maximum grain surface area from 4.9×10-7m2 increased to 3.56×10-6m2, and the average grain radius increases from 269.4μm to 410.2μm. Due to the solidification of steel 28MnCr5 gear and internal quality requirements, the superheat should be reduced as far as possible when other conditions were met.