Based on Meteorological industry standard of People's Republic of China-Division of climate season (QX/T 152-2012), using the temperature data of 122 stations of Yunnan from 1961 to 2017, this paper analyzes the spatial distribution of climate season regions and the trend of beginning dates and seasonal length. There are four climate season regions in Yunnan, namely regions with four seasons, non-summer region, non-winter region and perennial spring region. The area of non-summer region is the most extensive, non-winter region in the next place. The spatial distribution varies for four climate season regions in different decades. The spatial change is the most significant for non-summer and non-winter regions. After 2011, the area of region of four seasons in Yunnan has increased remarkably, which is consistent with the observation fact that the annual difference of temperature in Yunnan has increased under the background of climate warming in recent years. The length of spring and autumn is longer but summer and winter is shorter of region with four seasons in Yunnan. The length of autumn of non-summer region is the longest, followed by spring and winter. The length of summer of non-winter region is the longest while spring and autumn are close. The beginning dates of spring and summer show an early trend in different climatic season regions, and the autumn and winter show a delayed trend. To the change of seasonal length, summer increases and winter became shorter, but the length of spring and autumn varies in different climate season region.