The invention discloses a finned nuclear-grade heat exchanger high in seismic resistance and corrosion resistance. The finned nuclear-grade heat exchanger comprises a framework, water collecting tubes, base tubes, U-shaped bend tubes which are connected with the base tubes, and fins which are located inside the framework and perpendicularly connected with the base tubes. The framework is composed of a front tube plate, a rear tube plate, an upper frame plate and a lower frame plate. The front tube plate and the rear tube plate are both provided with base tube through holes used for supporting the base tubes. The base tubes are connected with the water collecting tubes through water inlet and outlet connecting tubes. The base tubes are connected through the U-shaped bend tubes, so that a coil pipe circulation pipeline is formed. The base tube through holes are provided with base tube protecting rings. The water collecting tubes are fixedly connected with a plurality of water collecting tube reinforcing braces, and the water collecting tube reinforcing braces are fixedly connected with the front tube plate through fasteners. The base tubes are connected with the U-shaped bend tubes and the water inlet and outlet connecting tubes through soldered joints with the socket and spigot joint depth being 6-12 times of the wall thickness of the base tubes. The finned nuclear-grade heat exchanger has the following beneficial effects of being high in seismic resistance, high in fin corrosion resistance, firm in overall structure, and stable, safe and reliable to operate.