Infrared thermography is introduced to measure the in-plane thermal conduction of woven carbon fiber reinforced polymers (CFRP). According to the principle of modulated laser heating, the relationship between the in-plane thermal diffusivity and the phase gradient is deduced, and the experiment platform is established to test the CFRP samples. Glassy carbon is used as the reference material, and the measured infrared radiation signal is normalized. The Gaussian filtering is applied to removing the noise of infrared thermal images. The experiment results show that the in-plane thermal conduction in various directions is related to the conduction direction owing to the anisotropy of CFRP. When the modulated frequency is lower than 2 Hz, the in-plane thermal diffusivity of samples in each direction can be measured.