The currently global climate changes characterized by increasing temperature have the potential to alter the hydrological cycle in regional and global scale.The intensifying meteor-hydrological extremes should be due to altered hydrological cycle.Sound understanding and good knowledge of probability behaviors of meteor-hydrological extremes are the first step into effective management of resources and enhancement of human mitigalion to natural hazards.In this case, the multivariate analysis method and the Copula function are used in this study with aim to investigate joint probability behaviors of high flow and low flow of the major tributaries of the Lake Poyang, the largest freshwater wetland in China.The results indicate that:(1) The joint return periods (JP) of high and low flows are shorter than the designed ones.However, the joint return periods given X>x and Y>y (JPS) are much longer than the designed ones.(2) Given the same designed return periods, the JPs of high flow at the Waizhou and Lijiadu stations are larger than those of low flow events.Besides, the JPSs of high flow are usually shorter than those of low flow, implying higher probability of high flow events at the Waizhou and Lijiadu stations.The probability of concurrent occurrence of high flow with return periods of < 10 years is larger than that of > 10 years.The JPs and JPSs of high flow and low flow events at the Hushan and Lijiadu stations are approximately similar, implying the similar probability of concurrent occurrence of high and low flow e-vents.(3) Given the same designed return periods, the JPs (JPSs) of high flow events at the Waizhou and Lijiadu stations are larger (smaller) than those at the Hushan and Dufengkeng stations.The JPs (JPSs) of low flow events at the Waizhou and Lijiadu stations are smaller (larger) than those at the Hushan and Dufengkeng stations.