Understanding the inconsistency in the effects of monsoon changes on drought and flood occurrences would allow scientists to identify useful indicators in the prediction and early warning of regional drought and flood. Based on the calculation of the Standardized Precipitation Index, monsoon indices, and water vapor fluxes from 1956 to 2015, the relationships between drought–flood occurrences and monsoons in different regions of the Lancang River Basin were investigated. Drought and flood occurrences had spatial differences. Areas located in the lower basin had high drought and flood occurrences. The frequencies of drought and flood occurrences have no obvious regional differences and mainly varied periodically at 3–5, 8–15, and 20–25 years. Because the impact and strength of the Tibetan Plateau Monsoon (TPM) and South Asian monsoon (SAM) are limited, the TPM and SAM are the key factors that affect the occurrences of drought and flood in the upstream and downstream regions of the Lancang River Basin, respectively. The TPM and SAM are potentially useful indicators in the prediction of drought and flood occurrences. These results are of great scientific merit in developing an effective mitigation strategy to reduce the impacts of drought–flood disasters in the Lancang River Basin.

了解季风变化对干旱和洪水发生的影响的不一致，将使科学家能够确定有用的指标，以预测和预警区域干旱和洪水。根据1956年至2015年的标准降水指数，季风指数和水汽通量的计算，研究了澜沧江流域不同地区的旱涝发生与季风之间的关系。干旱和洪水发生具有空间差异。下游盆地地区干旱和洪灾发生率很高。干旱和洪水发生的频率没有明显的区域差异，并且主要在3-5年，8-15年和20-25年周期性变化。由于青藏高原季风（TPM）和南亚季风（SAM）的影响和强度有限，因此TPM和SAM是影响澜沧江流域上游和下游地区干旱和洪水发生的关键因素， 分别。TPM和SAM是预测干旱和洪水发生的潜在有用指标。这些结果在制定有效的缓解策略以减少澜沧江流域旱涝灾害的影响方面具有重大科学价值。