The invention relates to a foam-assisted gravity oil driving method. The foam-assisted gravity oil driving method comprises the steps that a well is drilled as a production well at the lower part of an oil reservoir, a straight well is drilled as an injection well at the top of the oil reservoir, foam is continuously injected into the injection well, and the foam injection volume is controlled tobe 0.01-0.2 PV, oil is pushed in high and low permeable parts by using the foam, after being broken, the foam is accumulated to form a secondary gas cap to displace top attic oil, so that the more foam can enter the low permeable part, the high and low permeable parts achieve the effect of simultaneous propulsion, and sweep coefficient is improved; after the foam is broken, released gas enters thehigh part of a structure under the action of gravity differentiation, the gas is gathered continuously to form the secondary gas cap, the top attic oil is displaced, and the sweep coefficient is further improved; and a surfactant in a foam system can greatly reduce interfacial tension of oil and water, so that original oil in a restrained state becomes flowable oil, and the oil washing efficiencyis improved.