As the applied fields of ceramics enlarged, the quality of the ceramics parts was needed higher and higher. However, the designing and the manufacturing of the ceramics parts were separated, and the designing resolution had to be amended many times before it became the final resolution. In order to solve the problem that designing ceramics parts has to depend on experience, to save the cost and to shorten the manufacturing time, the simulation software on the temperature field of sintering complex ceramics parts was developed. First, the formula of temperature field was founded on the basis of the diathermanous theory. Second, the Finite Difference Method was used to deal with the formula of temperature field and make the core code of this software for calculating, thus the simulation of the temperature field of sintering complex ceramics parts and combined component was realized.