The invention discloses a dicyclopentadiene (DCPD) and carbon fiber cloth composite manhole cover and a manufacturing method thereof. According to the manufacturing method, a component A and a component B are adopted, are mixed through an injection machine mixing head according to the weight ratio of 1:1 and then are injected into a manhole cover mold pre-placed and fixed with carbon fiber cloth subjected to surface treatment, polymerization reaction and molding processes are preformed in the manhole cover mold, and thus the polydicyclopentadiene and carbon fiber cloth composite manhole cover is obtained; the component A comprises dicyclopentadiene and a main catalyst; the component B comprises dicyclopentadiene and an activating agent. With adopting of the reaction injection molding processing method, the processing process adopts one-time molding, the processing flow is greatly reduced, and the processing speed is improved; with adopting of dicyclopentadiene and the carbon fiber cloth as the materials, the manhole cover strength and rigidity are obviously improved, the manhole cover has the advantages of abrasion resistance, corrosion resistance, excellent rigidity, excellent impact strength, wide applicable temperature range and good heat resistance, and the service life is prolonged.