Research into the seasonal changes of infrared thermal images (ITI) of human body can be the solid foundation for clinical application of ITI in traditional Chinese medicine. Methods:Healthy university students had their images taken in summer and winter. The image features in two seasons were compared and the relation between the image features and Chinese medical constitution were discussed. Results:ITI displayed the thermal differences between seasons of the human body surface, and suggested specific image feature was related to certain the Chinese medical constitution. In winter, thermal difference of different body parts were greater than that in summer, such as upper part vs. lower part of the body, thigh vs. cruis, two sides of breasts. Conclusion: ITI can reflect thermal changes of human body over the season, therefore it is helpful to research on Chinese medical constitution.