In order to explore the relationship between the firing temperature of the clay coin moulds and whether they were founded successfully or not, the firing temperatures of series samples including the excavated samples from three coin foundry sites of the Liang Dynasty were tested and simulative samples by DIL are compared. The result for the excavated samples from the three coin foundry sites in Nanjing and Zhenjiang indicates that the firing temperature varies from 947[degrees]C to 1076[degrees]C, then the reasons for the abandoned moulds of the foundry sites are discussed based on those approaches, the result of the simulative samples which we knew when they were founded successfully or not shows, the firing temperatures of the clay moulds of the successful castings are 80[degrees]C to 90[degrees]C higher than the failed ones. A conclusion can be made that the firing temperature of the clay coin moulds is one of the key factors for successful foundry of ancient coins.