The interdecadal changes of temperature and precipitation over the Hetian river valley are analysed based on the data of temperature and precipitation observed in the Hetian weather station from 1961 to 2000. The results show that the climatic evolvement in the Hetian river valley has obvious both interannual and interdacadal scales. The average temperature and precipitation have upward trend of 0.26℃/10a and 1.56mm/10a respectively. The temperature rising trend is more obvious in 1990s. 1999 is the warmest year in the last 40 years.