This invention discloses a simple and convenient method of floods control and with great discharge capacity. This invention is a method of speeding up the river floods water discharge ability into the sea by means of the natural tidal range. This is done by the following technical proposals. To set up the PTCCG between the tidal current limit of the estuary and the coast tangent or narrower part of the estuary; the said PTCCG should be built across the river from the banks theoretically. When there is a danger of flood during the floods seasons, we can close the PTCCG and prevent the tidal current from entering into the inner river. When the tide ebbs, we can re-open the PTCCG and discharge the freshwater withheld into the sea. The PTCCG is normally open when it is not used. This invention is applicable to all tidal estuaries, which are affected by the astronomical tide range. It makes use of the natural tidal range to control floods in the upper stream of the river, which has a great floods control capacity, and accelerates the speed of floods discharging into the sea.