The invention provides a foaming drainage agent. The foaming drainage agent is prepared from components in percentage by mass as follows: 15%-30% of betaine, 25%-50% of amine oxide, 5%-15% of fatty alcohol polyoxyethylene ether sulfate, 1%-4% of alkyl glycoside and the balance of water. The invention further provides a preparation method and an application of the foaming drainage agent. Different types of surfactants with different functional group structures are compounded, so that a special synergistic effect is realized, compacter oriented molecule arrangement is formed, compactness and stability of foam are enhanced, foam performance is improved, condensate oil resistance is up to 50%, methyl alcohol resistance is up to 30%, mineralization resistance reaches 350,000 mg/L, liquid carrying capacity is 70% or higher, surface tension is 28 mN/m or lower, and the problems that a conventional foaming drainage agent is difficult to foam, the foam stability is poor and the liquid carrying amount is low in an extreme environment are solved.