Abstract: 【Aim】 The objective of this research is to determine the influence of El Niño on the occurrence of rice planthoppers in China， so as to illustrate the occurrence regularity of rice planthoppers under extreme weather. 【Methods】 The northward migration processes of rice planthoppers in the next year (2016) after an event of El Niño were analyzed based on the data of the weather over the East Asia migration field and population sizes of rice planthoppers monitored by light traps. The light trap catches of rice planthoppers in nine provinces of southeast China in the latest decade were statistically analyzed. Grid Analysis and Display System (GrADS) was used to visualize the weather processes during the migration of rice planthoppers. HYSPLIT trajectory analysis platform was used to simulate the endpoints of an emigration event of rice planthoppers from their population source areas. The essential weather  processes in the source areas of Indo-hina Peninsula to the main damage regions of the Yangtze River Delta were analyzed， and their effects on the secondary environmental factors were discussed. 【Results】 The 2015-2016 El Niño was one of the strongest events since 1980s. This event  resulted in significant influences on the weather of East and Southeast Asia. It caused the unprecedented worst drought in Indo-hina Peninsula，and heavy rain and floods in the south and east of China. It was found that： 1) the drought of IndoChina Peninsula in winter-pring brought about the decrease of the number of rice planthoppers in this area which would migrate to China； 2) the heavy rainfall in the south of China led to a barrier for rice planthoppers to migrate from south to north； 3) the waterlogging induced by rainfall made the number of eggs and nymphs in the fields hardly rise； and 4) high temperature in summer prevented planthopper population outbreaks. 【Conclusion】 The impacts of this El Niño on rice planthoppers are not only related to the own property of this extreme meteorological event， and some certain short-erm weather events  during the El Niño also might be crucial for the population development of rice planthoppers.

Key words: Rice planthopper； population outbreak； El Niñ, o； extreme climate； drought； flood