The invention relates to a double hydrophilic head-based anionic surfactant and a preparation method thereof, and mainly aims at solving the problem that in the prior art, a surfactant serving as an oil-displacing agent system component is poor in high temperature resistance, salt resistance and especially divalent cation resistance. According to the technical scheme, a general molecular formula of the double hydrophilic head-based anionic surfactant is as followed (please see the formula in the specification), wherein R1 represents C8-C10 aliphatic alkyl or aryl substituted by C4-C20 straight-chain or branch-chain saturated and unsaturated alkyl, R2 and R'2 are independently selected from at least one of C1-C5 alkylene or hydroxy-substituted alkylene, Y and Y' are independently selected from SO3M or COON, and M and N are independently selected from hydrogen or alkali metal or at least one of groups shown in a formula NR3(R4)(R5)(R6). Accordingly, the problem is better solved, and the double hydrophilic head-based anionic surfactant can be applied to production for increasing the crude oil recovery ratio in an oil field.