Belonging to the technical field of fine chemicals, the invention in particular relates to a synthesis method of calcium cyanamide. The method adopts calcium oxide, carbon powder and ammonia gas as the raw materials to synthesize the target product calcium cyanamide under the action of a catalyst, and the catalyst is one or more of calcium fluoride, calcium chloride and zinc oxide. The method provided by the invention has the advantages of simple operation steps, low energy consumption, short production cycle, high product yield and purity, and meets the quality requirements of the market forcalcium cyanamide; the raw materials are easily available and cheap, and have no geographical limitation; the reaction does not generate waste, and has high environmental protection value. The methodgreatly lowers the production cost, improves the product yield and quality, and is suitable for industrial production.