Abstract: A unit cell model based on meso-structure and fabrication procedure was presented for the in-plain coefficient of thermal conductivity for 2D braided C/SiC composites. In this unit cell model，the actual strand cross-section geometry was simplified and the void caused by the possible gap between two adjacent strands was taken into account. The influence of structure parameters on the 2D braided C/SiC composite's coefficient of thermal conductivity was predicted. The predicted results show that the composite's coefficient of thermal conductivity decreases with the increase of kinking distance，as well as，decreases with the increase of fiber volume fraction and void volume fraction. The test result shows that there is a good correlation between the predicted results and the experimental values.