The invention relates to a storage tank cleaning system which comprises a tank body, a lifting mechanism, and cleaning equipment connected with the lifting mechanism. The cleaning equipment comprisesa control assembly, a connecting assembly detachably connected with the control assembly, and a water spraying assembly detachably connected with the connecting assembly, wherein the control assemblycomprises a fixed frame, a center control piece connected with the fixed frame, and a drive piece connected with the fixed frame; the center control piece is electrically connected with the drive piece; the connecting assembly comprises a support frame, an electric wire roller and a wound tube roller pivoted onto the support frame, a guide wire connected with the electric wire roller, and a watertube connected with the wound tube roller; the guide wire is electrically connected with the center control piece; the water tube is connected with the drive piece; and the water spraying assembly isconnected with one end, back to the drive piece, of the water tube. According to the cleaning equipment, through arranging the drive piece, the water tube and the water spraying assembly, the inner part of the external tank body can be automatically cleaned, and a worker has no need to enter the tank body to manually clean the tank body, so that the cleaning efficiency is further improved, and thefatigue strength of the worker is reduced.