Abstract: The thermal expansion strain in parallel direction of carbon fiber reinforced resin composite was tested by fiber Bragg grating sensor. Layer model and modified model were used to calculate the thermal expansion strain in parallel direction respectively. The experimental results were compared with the calculated results. Thermal stress in perpendicular direction was calculated by modified model and ABAQUS finite element software separately, and the software was also used to simulate the effect of fiber arrangement on thermal stress, thus the distribution of thermal stress was obtained. The results show that with the increase of temperature, the thermal expansion strain of the composite increased linearly, thermal stress of fiber concentrated region was 1.5 times greater than other areas, stress concentration phenomenon occured at the interface between fiber and the substrate. Compared with the layer model, the thermal strain calculated by the modified model was more accurate, and the error between modified model and the experiment result was less than 10%, this indicating the accuracy of modified model and the reasonableness of the finite element model.