The invention discloses a self-foaming-type foaming drainage agent. The self-foaming-type foaming drainage agent comprises, by weight, 20-40 parts of soapberry fruit saponin, 8-25 parts of sodium fatty acid methyl ester sulfonate, 8-25 parts of 1-hydroxyethylidene-1,1-diphosphonicacid, 10-30 parts of sodium bicarbonate and 10-30 parts of tartrate. The preparation method comprises the following steps of S1, weighing: weighing the raw materials according to the above ratio for next use, S2, drying: drying the weighed raw materials so that water content is less than 3%, and S3, pressing: adding all the dried raw materials into a mixer, carrying out stirring for 4-8min, transferring the mixture into a hydraulic press and carrying out processing to obtain round rod-shaped solids which are the self-foaming-type foaming drainage agents. The self-foaming-type foaming drainage agent realizes natural gas well foaming drainage of a water-blocked gas well or a natural gas well with a weak stratum capability, has dual effects of gaslifting and a foaming drainage agent, has a strong self-foaming capacity and a high liquid carrying rate and can produce effects fast. The preparation method has simple and convenient processes, has a low production cost, is environmentally friendly and is suitable for industrial large-scale production.