The invention discloses a dual-reservoir self-adjusting tidal power generation method and the system thereof. The tidal power generation system is composed of an upper reservoir, a water inlet gate of the upper reservoir, a pressure pipeline, a water-turbine generator set, a lower reservoir and a water outlet gate of the lower reservoir. The water inlet gate of the upper reservoir and the water outlet gate of the lower reservoir adopt the jacking-shaft type hydraulic power self-regulation gate, so that the upper reservoir can fully introduce the tidal water, and the lower reservoir can fully discharge the tail water of a power station; furthermore, the inertia rise and fall of the tide are utilized, thus keeping the working head of the water-turbine generator set to the maximum extent, thus effectively improving transformation efficiency by utilizing the tidal energy to generate power, and solving the problems with a tidal power station, such as sediment accumulation, etc. Compared with the previous tidal power generation system, the novel tidal power generation system has the advantages of high energy conversion efficiency, long service life, simple structure, convenient operation, all-weather continuous generation, saved investment, research and promotion value, etc.