The invention discloses a rectification type auto-cascade low-temperature condensation oil-gas separation system with cooling capacity recovery. The system comprises a compressor, a condenser, a rectification device and an oil-gas condensation separation and cooling capacity recovery loop, wherein the oil-gas condensation separation and cooling capacity recovery loop comprises a first heat exchanger unit, a second heat exchanger unit, a third heat exchanger unit, a first restricting element and a separator unit. According to the system, the rectification device is adopted to replace multi-stage separation process of a conventional mixed working medium auto-cascade oil-gas separation system, meanwhile high-pressure liquid refrigerants of different components are respectively led out from the bottom and the top of the rectification device, condensed oil is precooled, is respectively depressurized, is fed into the first heat exchanger unit and is optimized to be matched with water equivalent weight variations of oil gases of different components in the cooling process. The system has the advantages of being simple in structure, reliable in operation, good in energy conservation and the like, and is particularly applicable to treatment on volatile oil gases in places such as oil depots, petrol stations and chemical treatment plants.