By use of data of annual average temperature, annual precipitation, pan evaporation, and annual average surface wind speed collected at 131 stations from 1960 to 2003 in Northwest China (covering the provinces and regions of Xingjiang, Qinghai, Gansu, Ningxia, Shanxi and the west of Inner Mongolia), the climate change characteristic was analyzed for the last half century. The result showed that temperature display marked increasing tendency in Northwest China except in the southeast of Qinghai and fraction area of Xinjiang, and the tendency rate was 0.2~0.9℃/10a. Sudden change took place from low to high in 1994; it was found that annual total precipitation showed increasing tendency in westerly climate region of Northwest China. Decreasing tendency in Monsoon climate region of Northwest China displayed, but the tendency was weak; it was proved that pan evaporation showed decreasing tendency in whole Northwest China, and sudden change took place from more to few in 1976; it was also found that the main cause which pan evaporation was decreased was likely the decrease of surface wind speed, sunlight duration, average daily range and the increase of relative humidity, average low cloud cover.