Abstract: Through the principal component analysis of two climatic elementssunshine and relative humidity,the dominant distribution patterns both of perennial sunshine duration deviation(3)and perennial relative humidity(Fig. 3)in the northeast region were defined.The author used the results derived from the principal component analysis of perennial monthly mean atmospheric pressure(Fig.1)to explain the cause and process forming dominant distribution patterns of perennial sunshine deviation(Fig.2)and relative humidity deviation(Fig.4),and approach the regional characteristics of two climatic elements with time change.The similarity(distance Fig.5)among the clusters was obtained with the group average method and based on the time changing eigenvalues(factor loading)of principal components of sunshine and relative humidity correlated respectively with sunshine and relative humidity in observation stations and points.The author took the similarity as the comprehensive indexes for regionalization to map the regionalization of time changing characteristics of sunshine(Pig.6)and the regionalization of time changing characteristics of relative humidity(Fig.7)in the northeast region.Finally,the author pointed out that using the cluster analysis method of principal components to regionaliza the climatic elements was a new method for regionalization.therefore,it is of great significance in the research on regional climatic characteristics,especially on regionalization or classification theory,and in the practical application of qualitative system combined with quantitative system.