The invention relates to a foam dehydrant composition and a preparation method and application thereof, and belongs to the technical field of petrochemical industry. The efficient foam dehydrant composition provided by the invention is prepared from the following ingredients in parts by mass: 1 part of alkylamine polyether benzene sulfonate and 0.1-50 parts of long-chain polyether nitrogen containing compound. By adopting the technical scheme of the invention, proven by test on foam performance of a foam dehydrant according to SY/T 6465-2000 evaluation method of foaming agent for foam water drainage and gas production, in brine with the degree of mineralization of 0mg/L to 200,000mg/L, the foaming height is greater than 200mm, the liquid carrying amount is greater than 150mL, and after aging at the high temperature of 180 DEG C for 24h, the foam foaming height and drainage performance change rate are smaller than 5%, so that the efficient foam dehydrant composition has good temperatureresistance, salt tolerance, foaming performance and liquid carrying capability, and a relatively good technical effect is achieved.