Currently, Vietnam has been strongly developing hydropower reservoir systems in main river basins, where there are hydropower reserves to produce electricity and exploit and use water resources effectively. Risk reduction to meet socio-economic development requirements in downstream areas. The multi-reservoir and multi-purpose operating mechanism must ensure both the. power generation and the sufficient water supply for the socio-economic development needs o f the downstream area. This paper will present the. approach for optimal operation o f the. multi-purpose, reservoir system on upstream o f the. Ca river following the. approach o f both optimizing the. amount o f electricity generated and ensuring water supply for downstream development needs. Instead o f a multi-purpose approach to power generation and downstream water supply, the. optimal model is transformed into a single-target optimization objective, the. economic benefits o f electricity generation, water needs for economic development are. calculated according to the. scenario o f water use. and taking into the. model in terms o f constraints are. controlled discharges at downstream control points. Hie results o f the. optimal model will show the. coordination o f operations between the. Ban Ve, Khe. Bo, Chi Khe, and Ban Mong reservoirs corresponding to the. scenarios o f water use. and then choose, the. scenario o f optimal operation.