Abstract: At present, there exist issues in spacecraft thermal test involving intricate demands for thermal flux simulation, low efficiency in heating circuit design, and difficulty in quantification. Taking a set of thermal control simulation components of a mission as representative cases, temperature non-uniformity models corresponsive to the combination of various featured length components and thin film electric heaters were established through finite element method. A clustering method based on the temperature non-uniformity distance was presented. The clustering simulation was conducted based on MATLAB. Compared with the Euclidean distance clustering method, the results show that the temperature non-uniformity with the proposed algorithm can be reduced by about 30% under the same conditions. In addition, the influence of clustering number, heating surface fine fraction, and number of surfaces to be heated on the clustering results and temperature non-uniformity were compared. It may provide a reference for the layout design and optimization of heating circuits in the future thermal test.