The invention discloses a waterpower aeration system for a river. A control module starts an aeration device and a first oxygen content detection device for 10 to 15min at a test state, then receives oxygen content data of the first oxygen content detection device, and uses the oxygen content data as an oxygen content zero point for storing in a storage module; the control module is also used for closing the aeration device at a use state when the oxygen content data detected by a second oxygen content detection device is larger than the oxygen content zero point, and starting the aeration device at a use state when the oxygen content data detected by the second oxygen content detection device is less than the oxygen content zero point. According to the waterpower aeration system for the river provided by the invention, the real-time monitoring and the real-time aerating on the oxygen content of a river flow are realized, the river flow is effectively subjected to oxygen supplement, and the effective treatment on river eutrophication is further realized.