Abstract: Thermal conductivity is an important thermophysical parameter for evaluating the high-temperature service performance of composites, with significant temperature and damage dependence. This paper aims at characterization and prediction of thermal conductivity of 2D-C/SiC composites. Firstly, the closed solution of the longitudinal thermal conductivity of fiber bundle with matrix cracks and interface debonding damage is presented based on concentric cylinder shear-lag model, thermal resistance series/parallel law and homogenization method. Meanwhile, the analytical equation of the transverse thermal conductivity of fiber bundle with debonded interface is provided according to the effective medium theory. Subsequently, an idealized single-cell model was established with consideration of the microstructure of plain-woven ceramic matrix composites and the characteristics of their preparation techniques, and an analytical prediction model for the macroscopic equivalent thermal conductivity of the composites is developed by the thermal resistance grid method. Finally, the theoretical model is validated based on the in-plane experimental data of 2D-C/SiC, and the main influencing factors of the thermal conductivity were analyzed and discussed. The parametric analysis shows that the fiber volume fraction, pore content, geometrical structural parameters of the fabric, matrix crack spacing and interfacial debonding rate all affect the thermal conductivity of 2D-C/SiC composites. The verification results show that the present model is reasonable and accurate, and its predicted values are in good agreement with the experimental data.