The negative accumulated temperature is an index of cold degree in winter. Theoretically,its change associates with permafrost development. In this paper, empirical orthogonal function, wavelet transform, as well as cluster analysis, are used to analyze the negative accumulated temperature in Northeast China, aiming to explore the spatial and temporal variations of negative accumulated temperature, to acquire its relation with permafrost degeneration and annual mean temperature change. The results showed that from 1957 to 2007,the negative accumulated temperature in Northeast China, which was calculated from 81 meteorological observation stations, had increased. The increase rate during the 51 years had decreased progressively from northeast to southwest of the study area. From 1957 through 2007,the study area can be divided into three periods according to the negative accumulated temperature, i. e., cold,warm and cold periods. In the Da Hinggan Mountains and the northern Xiao Hinggan Mountains, The warm periods were shorter, with large annual and interannual amplitudes of vibration. Except in north of Heilongjiang Province and east of Inner Mongolia Autonomous Region, the lowest, highest and mutation years of negative accumulated temperature were the same, which indicated the regional synchronization of accumulated temperature change. The increase of negative accumulated temperature was in accordance with permafrost degradation and the increase in annual mean temperature.