Abstract: According to heat transfer, filtration theory and mechanics of frozen soil, a mathematics model and its control equation were put forward, which is of the coupling problem of temperature field, water field and stress fields. By utilizing the program developed by ourselves and the constitutive relation and mathematics mechanics model which we built up, numerical analysis was carried out to obation moisture, temperature and stress fields of frozen roadbed. The result agreed with actual temperature field coupled with stress field, moisture field and strain field, and is consistent with the result of predecessors and the test result.