The invention relates to polyoxyethylene-ether-containing hydroxypropyl anilino carboxylate betaine and a preparation method thereof, and mainly solves the problems in the prior art that an oil-displacement agent containing a surfactant is bad in oil displacement effect and high in use concentration under the oil reservoir conditions of high temperature and high salinity, and alkalis in alkali-surfactant-polymer flooding pollute and damage stratum and oil wells and severely corrode equipment and conveying pipelines. The polyoxyethylene-ether-containing hydroxypropyl anilino carboxylate betaine has the molecular general formula (I) shown in the specification, and in the formula (I), R1 is any one of C15-C39 alkyl and alkenyl, n is 1-10, R2 is any one of C1-C4 alkylidene and hydroxyl-substituted alkylidene. The technical scheme relatively well solves the problems and is applicable to tertiary oil recovery of oil fields.