An integrated power system combining tidal power generation and ocean current power generation comprises: constructing barrages across the sea to make up a lake; installing turbine structures of a tidal power plant and sluice structures of a tidal power dam for generating electricity by using the potential energy difference between seawaters caused by tides and ebbs; forming an ocean current power park in a lake side by installing a plurality of ocean current generators, for generating electricity by using the flow of the seawater discharged through turbine generators, in a rear lake side of the turbine structures of the tidal power plant; and forming an ocean current power park in a sea side by installing ocean current generators, for generating electricity by using the seawater with the fast speed discharged into the sea through sluice gates, in a rear sea side of the sluice structures of the tidal power dam.