The invention provides a membrane cleaning device applicable to a submerged membrane bioreactor. A micrometer and nanometer air bubble generator is used for replacing the traditional perforated aerator pipe, high-pressure water flows rich in micrometer-scale and nanometer-scale air bubbles are generated in the membrane bioreactor, while necessary oxygen for the microbial reaction is supplied, a good flushing effect is realized on a membrane assembly. The membrane cleaning device comprises the micrometer and nanometer air bubble generator and an oxygen supply system, wherein the micrometer and nanometer air bubble generator comprises a micrometer and nanometer air bubble generator host and aeration heads, an air dissolving device and a booster pump connected with the air dissolving device are arranged in the host, an air inlet of the air dissolving device is connected with the oxygen supply system, a water inlet of the air dissolving device is communicated with the membrane bioreactor, a water outlet of the air dissolving device is connected onto a plurality of aeration heads arranged in the membrane bioreactor through connecting pipelines, the aeration heads are uniformly arranged at the lower end of the membrane assembly arranged in the membrane bioreactor, and the directions of high-pressure water flows flowing out from the water outlets of all of the aeration heads are parallel to or tangent to the solid-liquid interface of a membrane of the membrane assembly.