Abstract: This paper compares the different ball milling efficiencies and methods by using different milling mediums (Self-designed Heptahedron Milling and Ball-milling) during WC-10 %Co's wet grinding preparation process. The analysis of sintered alloy properties shows the effect of different ball milling mediums on alloy properties. The results indicate that: The efficiency of Heptahedron Milling Medium is higher than Ball-milling by bringing more powder activity and oxygen-adding tendency during the mixture storage process. It therefore causes relatively lower cobalt and magnetism contents. Adding 0.2 % paraffin can prevent powder oxidation. Heptahedron milling medium is suitable for the mixture preparation with raw materials' Fisher particle size larger than 5.0 μ m, while ball milling medium is suitable for raw materials' Fisher particle size 0.8~5.0 μ m.