Based on the data such as sunshine duration, rainfall, cloudiness, mean wind speed, and day numbers of vision obstruction of 50 stations in the north China plain during 1961—2010 with modern statistical diagnostic methods such as linear trend analysis, cluster analysis, and abrupt detection, the temporal/spatial features and cause of yearly, seasonal, and monthly sunshine duration in the north China plain were investigated in this paper. The results showed that the spatial distribution of yearly, seasonal, and monthly sunshine duration in the north of the north China plain was more than that in the south of the plain. The yearly sunshine duration was 1910.6-2982.9 h, and the maximum was in spring, and next in summer, autumn, and winter. The yearly sunshine duration in the north China plain in the recent 50 a was obviously reduced(93.4 h/10a), the reduction was over 2 times more than that of the national average(-45.9 h/10a) at the same period. The significant decadal change was in the middle/late 1980s. The yearly sunshine duration was extremely excessive in 1965,and extremely deficient in 2003. Meanwhile the seasonal sunshine duration was also obviously declined, but it did not show an obviously positive trend in a single season at a single station. The maximum reduction was in summer, and next in winter, autumn, and spring. The reduction rate of the seasonal sunshine duration in summer and autumn in recent 30 a was found to increase, but it reduced slightly in winter and spring. The reduction of the sunshine duration in the north China plain might be ascribed to the decline of the atmospheric transparency and the reduction of the mean wind speed. Moreover the effect of the cloudiness in different regions was different.