The Tibetan Plateau is one of the best places to investigate global clim ate changes. Aridity or humidity of land surface has been paid more and more att ention by scientists and publics. On the basis of the mean annual air temperatur e, precipitation and relative humidity from 25 meteorological stations in the Ti betan Region from 1960 to 2001, the longterm trend of major climatic variables was analyzed by using MannKendall test method. The results showed that the ai r temperature, precipitation and relative humidity all exhibited an increasing t endency, and the MannKendall slopes are 0.31℃/10a, 0.96mm/a and 0.3%/10a, res pectively during the past 42 years. Over the Tibetan Region, the increases in 〖 CM(18〗temperature and humidity occur mainly inautumn, also occurring in spring; increase of temperature and a little decreasing humidity happen in summer. The increase of temperature is remarkable but relative humidity shows no increasing tendency in winter. The MannKendall test results showed that the air temperature exhibited an increasing trend in f our seasons, especially in winter. Summer contributed the most for the decreasin g trend of annual precipitation. Precipitation in summer exhibited a decreasing tendency. Relative humidity showed a declining trend in summer as well.