Abstract: The flood composition is complex and changeable in the Pearl River Basin, the flood protection objects are numerous and scattered, and multiple tasks such as water supply, ecology, power generation, shipping, reservoir area security, etc. should be taken into account. There are some technical problems on multi-region and multi-objective coordinated flood operation for reservoir groups in the Pearl River Basin. Taking the reservoirs located on the Xijiang River, Beijiang River and Dongjiang River as the research objects, based on the flood control pattern and tasks of the whole basin, the operation node and role positioning of multi-region coordinated flood control of reservoir group are clarified, the nested multi dimension attribute model functional structure is proposed, and the multi-region coordinated flood operation model of reservoir group in the Pearl River Basin is constructed. Taking the June 2005 flood that occurs in the middle and lower reaches, which is extremely unfavorable for flood control in the river basin, as an example, the flood regulation practice of the basinal reservoir group was carried out. The results showed that by increasing the storage capacity of Longtan Reservoir, and coordinating the operation of the reservoirs in Xijiang and Beijiang Rivers such as Yantan, Baise, Xijin, and Feilaixia reservoirs, the peak flow of Wuzhou Station in the Xijiang River can be reduced to below the safe discharge capacity of 50400 m³/s, which is lower some 3200 m³/s than the original designed scheduling plan, and the peak flow of Sixianjiao section(Makou+Sanshui) in the Pearl River Delta can be reduced to 62700 m³/s, compared to the original designed scheduling plan with the reduction of 4500 m³/s, effectively ensures the flood safety of the cities in the Guangdong-Hong Kong-Macao Greater Bay Area.