An anode for generating ozone by electrolysis of water, a preparation method and use thereof, an ozone generating system, and a dental scaler are provided. The anode includes a titanium substrate and a composite oxide layer attached to a surface of the titanium substrate. The composite oxide layer is made of a metal oxide. Metal elements in the metal oxide comprise tin, ruthenium, manganese, titanium, and nickel, and a molar ratio of tin, ruthenium, manganese, titanium, and nickel is (200-500):(2.5-20):1:(1.5-7):(5-15).