Abstract: A foam drive method for enhancing oil recovery efficiently is initiated by injecting into a subterranean oil-bearing formation, an aqueous polymer solution as a preceding-slug. This is followed by periodically injecting simultaneously or alternately a non-condensible gas and an aqueous solution of foaming composition to form a combined foam under ground or periodically injecting the combined foam formed beforehand by the gas and said aqueous solution above ground. The aqueous solution of foaming composition comprises an alkali, a surfactant and a polymer. Thereafter, an aqueous polymer solution used as a protecting-slug is injected into the formation; followed by continuing water-flooding.