Potential evapotranspiration is the theoretical upper limit value of actual evapotranspiration,which constitutes the important parameters for the research of regional thermal balance,water budget,water resources assessment and crop water requirements. Study on regional response of potential evapotranspiration to global climatic changes in China has significance in global hydrological cycling, energy balance and eco-environmental evolution research. Reference crop evapotranspiration (ET_0) as a common parameter is largely an evolution of definition of potential evapotranspiration and with the method of Penman-Monteith Model recommended by Food and Agriculture Organization for computing crop water requirements in 1998, reference crop evapotranspiration could be estimated quickly and accurately. Based on the daily observation data of the 56 meteorological stations in the North China Plain from 1960 to 2012, reference crop evapotranspiration were calculated, then the spatial-temporal variation patterns of reference crop evapotranspiration over North China Plain was analyzed with the methods of linear regression, spline interpolation and accumulative anomaly method. In the meantime, the dominant factors of the ET_0' s variations in North China Plain were quantitatively analyzed by calculating sensitivity coefficients of reference crop evapotranspiration to climate elements and the relative change of the climate elements. The result showed that: (1) Annual reference crop evapotranspiration of north China plain was 1071.37mm and the spatial distribution pattern was high center alternating with low center. The high value reference crop evapotranspiration areas mainly distributed in the northern Hebei,central part of Shandong mountainous region and western regions of Henan,while the low value centers distributed in the eastern regions of Hebei,southern Shandong,eastern and southern regions of Henan province. (2)The reference crop evapotranspiration has decreased obviously in North China Plain during the last 53 years by the rate of 12. 8mm/10a, and its decadal variation showed that the decade anomaly consistently decreased. From the perspective of the regional distribution of ET_0 change,the ET_0 of the northern Shandong Peninsular and the northern regions of Hebei province showed a slowly increasing trend,while the ET_0 of the rest areas decreased. (3) The sensitivity coefficients of reference crop evapotranspiration to the daily temperature (5_(AT)),sunshine hours (S_(SH)),wind speed (S_(ws)) were positive values,while the sensitivities coefficients of reference crop evapotranspiration increased slowly,while S_(RH) and S_(ws) decreased. There was a corresponding relationship for the sensitivity coefficients of reference crop evapotranspiration, which meand areas of high sensitivity to temperature and wind speed had relative low sensitivity to sunshine hour and the relative humidity.