Abstract: In June 2022, there were two basin-wide larger floods happened in the Pearl River basin and one catastrophic flood happened in the Beijiang River of the basin. The work of hydrological information delivery and flood forecast provided accurate and timely decision-making basis for the flood command of the basin during those floods, and the joint operation of the reservoir group had achieved good social and economic benefits. This paper describes and analyzes the Beijiang catastrophic flood process in June 2022, summarizes the flood forecast and early warning work and the existing deficiencies. It may provide some useful references for further improving the flood forecast and early warning work on the prevention of the basin-wide flood during joint operation of reservoir group. The result shows that the flood forecast scheme which is compiled by 11 stations of Beijiang River including Feilaixia Reservoir and Lechangxia Reservoir can meet the flood dispatching requirements of the basin. But there are some problems such as the short forecast period due to the impact of the forecast rainfall error, and the poor flood process forecast due to the model error in some section schemes, so the rolling forecast should be carried out in time according to the latest observed data. In addition, we shall give more attention to the real-time flow monitoring of the important reservoirs and the revision of the inflow flood forecast plan.