The manufacturing process of magnesite manhole covers belongs to the manufacturing technology of magnesite building materials products. The raw materials in this process are composed of main raw materials, skeleton materials and auxiliaries. The main raw materials include magnesium oxide, brine solution and quartz sand. The skeleton materials include fiberglass cloth and other materials. The additives used are patented products of the Shandong Academy of Construction Sciences. The main ingredients are ethyl silicate, iron ions, phosphoric acid, etc. The weight percentage of the additives in the main raw materials is 0.5-0.7, the main raw materials and auxiliary materials are mixed and stirred before casting. The tested flexural strength (MPa) of the manufactured magnesite manhole covers: 10.75 before freezing and 9.8 after freezing. Compressive strength (MPa): 55 before freezing and 65 after freezing. Load performance test: 30T car rolled back and forth 10 times without damage. .