A series of experiments was performed on studying the dynamic heat and moisture transferring procedure and evaluating heat and moisture comfort properties of different weight cotton fabrics. In experiments, the real time changes of temperature and relative humidity in inner and outer surfaces of different cotton fabrics were measured using self-made textile-microclimate measuring instrument. Then, the temperature and relative humidity in inner surface of fabric, and the difference of temperature and relative humidity between inner and outer surfaces of fabric were analyzed. Finally, in order to evaluate cotton fabric's dynamic heat comfort property and dynamic moisture comfort property comprehensively, two dynamic values were introduced to make evaluation. Results show that as the increase of cotton fabric's weight, fabric will have better thermal insulation performance and worse moisture permeability performance.