Abstract: In order to grasp the climatic characteristics and causes of cold and warm winter over Linyi City, based on the 12 to 2 monthly average temperature data in Linyi from 1961 to 2011, using the statistical methods to climate diagnostic studies, the variation trend of winter mean temperature over Linyi during recent 51 years was analyzed, on this basis, according to the China national standard warm winter grade and referring to single station and regional warm winter grade standards, the grade of single station and regional cold winter were determined. On the basis of the division method for cold and warm winter, the author analyzed the climatic change events of 10 stations’cold and warm winter in Linyi from 1961 to 2011. The results showed that: the trend of average temperature in winter increased significantly over Linyi, especially more obvious since the 1990s. Both IWs and IWa showed a significant upward trend, there were 10 regional warm winter years over the 51 years with 3 strong warm winter, and mainly after the 1990s, the frequency of single cold winter was 47%-59% with 20%-31% of strong cold winters, and ICd showed a significant decreasing trend at a decadal rate of -17.7%. There were 27 regional cold winter years over the 51 years with 14 strong cold winters, and mainly before the 1980s, significantly reduced after 1990s. The main factors of cold and warm winter attributed to the greenhouse effect, the weaken east Asian winter monsoon, the strengthened subtropical high in the western Pacific, ESNO etc, one of the most important and direct reason depended on the intensity and frequency of cold air, strong and frequent cold air, it would be a cold winter, and weak and low frequency was prone to warm winter.