The invention provides a three-section type energy-saving flap valve which is simple in structure, reasonable in design, and capable of conveniently preventing riverway water from being poured into sewers and smoothly draining away water in normal water level of a riverway. The three-section type energy-saving flap valve is composed of more than two sections of flap valve plates in sequence in a hinged mode. When the water level of the riverway is normal, little sewage in the sewer can burst through the flap valve to be smoothly drained, and when the water level of the riverway is high, the flap valve is closed, and water in the riverway can not pour back to the sewer.