Abstract: In terms of the yearly average data obtained from 123 routine meteorological observatories located over Tibetan Plateau, the decade characteristics of climate change over the Plateau in the recent 40 years are studied. It is found that in the mid-late 1980s, an evident climatic sudden change happens to yearly average temperature rainfall and relative humidity, featured by the increasing of them. The climate of the Plateau shifts to warm-wet period from warm-dry period at the sudden turning point. The climatic sudden change of temperature and rainfall are earlier than that of relative humidity over the target region. Over the Plateau, the increases in temperature and humidity occur mainly in winter and these increases, also occurring in spring, show slow range; increase of temperature and somewhat lowered humidity happen in summer; autumn is a season for remarkable increase of temperature but humidity shows no tendency of its change。