EOF analysis of accumulated temperature of 20 stations over Ningxia shows that the accumulated temperature and growth season increase with the global warming in Ningxia. The greaterthan0 ℃ and greaterthan5 ℃ accumulated temperatures have a very similar variation trend: increasing from 1997 to 2004. The greaterthan0 ℃ accumulated temperature is smaller before the middle 1980s and greater afterwards. The greaterthan5 ℃ accumulated temperature curve has a break in the middle 1990s, smaller before and greater after. The greaterthan10 ℃ accumulated temperature is greater or smaller than normal in the whole region in 60.1% years and has the opposite variation trend in the northern and southern parts with the boundary from Zhongning to Yanchi in 31.6％ years. The growing season shows the clear interdecadal variation trend with an increasing rate of 3.8 days per 10 years, especially the average of the first four years of the 21st century is 14.9 days more than that in the 1960s.