Abstract: Refrigerated infrared detector components have a wide range of applications in military, industrial, and medical fields, among others. Dewar components consist of a chip and a dewar, where the latter provides the necessary and reliable working environment, as well as optical, electrical, and mechanical interfaces for the chip. To meet the requirements of automated thermal design for Dewar components, the Creo/Toolkit secondary development tool within Creo is employed, in conjunction with Visual Studio 2017, to implement a method for automatically extracting model parameters and calculating thermal design data. The proposed approach executes algorithms within Creo to extract parameters such as mass, volume, density, and surface area. Each component in the assembly is accessed sequentially, and the extracted data are exported to Excel for further calculation of heat and heat load. This study presents the algorithm development process in detail, including data extraction, Excel interface development, and thermal design calculations. Experimental results show that the proposed algorithm improves both design efficiency and calculation accuracy, making it suitable for the thermal design of complex mechanical models. The findings provide a novel solution and technical support for automation in CAD software.