In addressing the requirements of water resources monitoring tasks, we propose an adaptive multi-sensor performance measurement scheme by integrating time-space coverage, sensor parameters, imaging quality, and target importance based on the prototype of the monitoring task requirements. To achieve optimal benefit for water resources monitoring tasks, we constructed a combined optimization method using fuzzy greedy search decision algorithm and validated the adaptability of the proposed method by applying it to the Danjiangkou Reservoir area. Results demonstrate that the combined observation method effectively meet the requirements of reservoir water quality monitoring, reservoir bank environmental monitoring, as well as routine drought monitoring tasks within specific space-time constraints, thereby providing a sound decision-making basis for the daily monitoring of water resources.