The invention relates to an anti-backflow one-way valve, belonging to the technical field of fluid flow valves. On the basis of a hydrodynamic design, (1) an upper valve blade and a lower valve blade are automatically expanded and closed without the action of external force; (2) the upper valve blade and the lower valve blade are not tensioned or supported by a spring and are opened without initial energy, so that the energy consumption of a system is reduced; and (3) the resistance of the system is the minimum through fluid calculation optimization, the total resistance of an air filter is added as little as possible, and the energy consumption of the system is further reduced.