Overland runoff rainwater storing and purifying integrated device with flooded culvert pipes and overland runoff rainwater storing and purifying method

The invention relates to an overland runoff rainwater storing and purifying integrated device with flooded culvert pipes and an overland runoff rainwater storing and purifying method. The device comprises a pre-precipitating chamber (2) and a wet land unit (2), wherein overland runoff rainwater passes through a perforated partition (4) and enters the wet land unit (2) after being precipitated preliminarily; the perforated culvert pipes (3) are arranged in the wet land unit (2) side by side; the culvert pipes (3) transversely penetrate in two sides of the wet land unit (2); perforated plugs (12) are arranged at two ends of each culvert pipe (3); the wet land unit (2) comprises a gravel cushion layer (9), a sand filter layer (8) and a planting soil layer (7); and perforated drainage pipes (5) are buried in the gravel cushion layer (9). By using the device and the method, particles and soluble pollutants in the runoff rainwater can be removed, so that the pollutants in the runoff rainwater are eliminated; and the treated rainwater is stored in the device and the culvert pipes (3), wet land plants can grow by using the treated rainwater, the water seeps to surrounding soil by submerging two ends of each culvert pipe in a wet land, and the purpose of continuously cultivating and supplementing underground water is achieved.