The invention provides a large-diameter diamond grinding wheel special for coarse grinding of a silicon nitride ceramic ball and a manufacturing method thereof. The large-diameter diamond grinding wheel is a round plate and comprises a base material and a grinding body. An installation hole is formed in the middle of the large-diameter diamond grinding wheel. The base material is made of a casting iron plate, and the grinding body is made of diamond and metal powder and pressed into the base material through high temperature heating. The grinding body is tightly combined with the base material. The porosity of the diamond grinding body is lower than 5%, the diameter of the large-diameter diamond grinding wheel is 800-1000 mm, the diameter of the working face of the annular end of the grinding body is 200-240 mm in the radial direction, the surface of the grinding body is smooth, deformation is avoided, and the large-diameter diamond grinding wheel is used for coarse grinding of the silicon nitride ceramic bearing balls. The total volume of the metal powder accounts for 50%-81.25% of the volume of the grinding body, and the metal powder comprises multiple kinds of powder including cobalt powder, tungsten powder, iron powder, tin powder, nickel powder, bronze powder, copper powder, titanium powder and zinc powder. The metal powder further comprises dispersing agent and wetting agent. Compared with a current domestic product, the grinding efficiency is improved by 6 times, and the large-diameter diamond grinding wheel is environmentally friendly and free of pollution when used.