With the deepening of new electricity system reform，the goal of hydropower dispatching has been transformed from maximizing power generation to maximizing power generation profit． According to the requirements of electricity market rules， hydropower suppliers need to bear the assessment cost of the deviation of electricity． Therefore，in addition to obtain more power generation indicators and higher electricity prices，hydropower suppliers should also control power generation deviations and avoid deviation assessment． Based on the current electricity market environment，a hydropower mid － long term scheduling model is constructed based on regional electricity market rules． The rationality and effectiveness of the proposed model are verified by an example analysis．