Abstract: This paper studies the dynamic efficiency of hydropower by decomposing the Malmquist index of hydropower in the Yangtze River mainstream region from 2014 to 2017,and uses the two-hierarchy Meta-frontier DEA model to conduct a static study on the technology gap ratio of hydropower in the Yangtze River mainstream region in 2017. The results show that the technology progress efficiency of hydropower in the Yangtze River mainstream region from 2014 to 2017 is generally on the rise,and the scale efficiency and total factor productivity of hydropower in the upper stream are lower than those in the middle stream and lower stream. In 2017,the technology gap ratio in the lower stream of the Yangtze River was lower than that in the upper stream and middle stream,and the geographical conditions were the main causes of the low technology gap ratio in the lower stream of the Yangtze River.