Subway station outer wall structure and construction method thereof

The invention discloses a subway station outer wall structure and a construction method thereof, and the subway station outer wall structure comprises an underground diaphragm wall which comprises a plurality of unit walls connected end to end, and each unit wall comprises a reinforcement cage and concrete wrapping the reinforcement cage; the water blocking film comprises a plurality of unit diaphragms and a splicer, the unit diaphragms are laid on the outer side of the unit wall, the lower ends of the unit diaphragms are connected to the reinforcement cage through rope buckles, each unit diaphragm is provided with two opposite adjacent sides, the splicer comprises two water stop steel plates, the adjacent sides of the unit diaphragms are connected to one side steel edge of one water stop steel plate, and the splicer is connected to the other side steel edge of the other water stop steel plate. The steel edge on the other side of one water stop steel plate is meshed with the steel edge on the other side of th