In order to master the indoor thermal environment of the traditional dwelling houses in dry hot and dry cold climate zones in winter, the east Gansu province is taken for example to study. Indoor and outdoor air temperature, relative humidity, solar radiation intensity and wind speed were obtained by using field-tested methods for the traditional dwelling houses in this region in winter, and the clothing form and activity of people were surveyed by way of questionnaire. And then, the influence of house orientation, indoor heat sources and insulation on the indoor thermal environment is analyzed, the WCI (wind chill index) is used to evaluate the indoor and outdoor thermal environment at last. The results show that: the indoor temperature can raise about 8.3 °C when the house orientation is better and Chinese kang as the heating heat source. The good practice on local structure is worthy of following for other houses, such as adobe posted solid brick wall, double windows, wooden sash windows and so on. However, people still feel very cool or cold about the indoor temperature for much of the day, and even people feel very cold for 5% of the day. At the end of thesis, some methods about the indoor thermal environment improvement are proposed.