Based on the monthly average temperature data over the Loess Plateau during the period from 1964 to 2014, the variation trend of winter mean temperature over the plateau in recent 50 years was analyzed using the methods of statistical analysis and Mann-kendall mutation analysis. According to the warm winter grades of China national standard referred to those at single stations and the regional warm winter grade standards, the warm winters for single stations were divided into two grades designated as theweek warm wintersandstrong warm winters, and the regional warm winters were analyzed based on the warm winters at single stations. In accordance with these standards, the warm winters were analyzed using the methods of Inverse distance weighted interpolation,wavelet analysis, etc. The results showed that the mean temperature in winter was increased with a rate of 0.07 - 0.695 ℃·(10a)~(-1) in recent half century,especially in recent 30 years, it was significantly warming up over the Loess Plateau,and it entered a relatively warm period. The temperature increase was the highest over the central Loess Plateau,but relatively low in the west and south. There was an obvious increase trend of warm winter index with rates of 0.07 - 0.70 ℃·(10a)~(-1) for single stations. The increase of warm winter index was the highest in the most of the central area, it was followed by the south area and was the lowest in the west area. The frequencies of warm winters and strong warm winters at single stations varied in ranges of 40% - 63% and 13% - 53%, respectively. The warm winter frequency at single stations was high in the central and western regions but low in the southeast marginal zone. Regional warm winter index was in an obvious increase trend with a rate of 11.8% · (10a)~(-1). There were 17 regional warm winters and 6 regional strong warm winters in recent 50 years. Moreover, there were 4 - and 9 - year periodic variations of regional warm winter, the warm winters occurred mainly in the period from the mid-to late - 1980s,especially in the period from late - 1990s to the early 21th century.