In order to investigate the decadal characteristic of ET0 in China and seek for the possible driving mechanisms, the regional mean anomalies of annual ET0, precipitation (P) and the climatic water availability (CWD, defined as P minus ET0) as well as its relationship to the Pacific Decadal Oscillation index (PDO) are analyzed. Although as a whole, the regional ET0 record shows a significant decrease trend of 0.298 mm yr−2 (p < 0.1) during the past 50-years period, the evolving process of continental mean ET0 can be clearly divided into three stages. From 1961 to 1979, ET0 present a slight but not significant decline (0.008 mm yr−2) with a high mean value. A prolonged significant decline starts in the year of 1980 and ends in the year of 1995, being contrary to the previously reported upward actual evapotranspiration in this period262728. This may partly be explained by the complementary relationship29 between ET0 and actual evapotranspiration. After 1996, a pronounced recovery growth rate in ET0 can be clearly revealed. An overall oscillation in regional mean ET0 is found in China, which was not revealed by the previous studies, suggesting that the variation of ET0 from 1961 to 2011 should be a phenomenon of earth’s atmospheric circulation. PDO is considered as the important earth’s climatic driving power for the continental hydro-meteorology abnormality such as shift of dry/wet in Asia, especially in China30313233. The PDO driven climate oscillations impart clear influences to the regional ET0 in China as a whole, indicated by significant negative correlation between annual PDO index and annual mean ET0 (r = −0.384; p < 0.001). Years with high ET0 mostly coincide with PDO cold phase although ET0 responses to PDO may differ in different sub-regions in China. On the other hand, years with low ET0 correspond to PDO warm phase conditions (Fig. 5). The regional mean P in China present large temporal variability with a negative but not significant trend of 0.257 mm yr−2 (p = 0.564) during 1961–2011, while the CWD present a significantly no trend although the slope is slightly positive with the value of 0.041 mm yr−2 (p = 0.938), suggesting that there is a weak tendency to reduce the deficit between atmospheric moisture requirement and available water supply for evapotranspiration. Despite of the strong relationship between regional ET0 and PDO activities, the CWD is not significantly correlated with PDO (r = 0.164, p > 0.1) due to the weak relationship between P and PDO (r = 0.045, p > 0.1).