In the optimal operation of hydropower stations, an optimal decision obtained by deterministic optimization for a certain period is influenced by the inflow in the adjacent periods. Due to the instability of inflow, the operation rules for some periods often become extremely complicated, resulting in a difficulty in rule derivation. To solve this problem, this paper presents a new idea of extracting staged operation rules using explicit mechanism and a practical method that divides the scheduling period into two parts, a stable period and a transition period, according to the rule patterns thr...