Disclosed are an environmental and degradable chemical flooding system and a preparation method thereof. The preparation method comprises adding, by weight part, 20-40 parts of acrylamide monomers, 2.5-6.5 parts of octadecyl long-chain vinyl monomers, 8.5-19.2 parts of sulfonate type vinyl monomers, 1.5-2.6 parts of emulsifier I, 2.6-4.5 parts of emulsifier II and 0.035-0.1 part of initiator into a reactor for reaction at 70-85 DEG C for 4-6 hours to obtain an amphiphilic high-polymer surfactant A; under the reaction of 2-4 parts of cosolvent, compounding 8.5-11.5 parts of the amphiphilic high-polymer surfactant A with 16-28.6 parts of an ultra-low interfacial tension system B to obtain the environmental and degradable chemical flooding system. The surface tension of the prepared environmental and degradable chemical flooding system is higher than that of a pure micromolecular surfactant flooding system, and can reach up to 0.015 mN/m, and can be increased by 13.5% on the basis of water flooding.