A method for controlling a subsidence area caused by underground mining in an adjoining open-pit mine, applied in an open-pit and underground coordinated mining process. In the method, a ground subsidence area caused by underground mining and production is directly filled and covered with overburden materials such as soil and rock discharged from an adjoining open-pit mine; small and medium fracture zones and large fracture zones caused by mining are timely backfilled, tamped, and levelled according to areas before the ground subsidence area appears, the thickness of the levelled soil layer is kept above 1 m, and the area slope is controlled within 7°. By fully using overburden materials from an adjoining open-pit mine, the method controls a subsidence area caused by underground mining and greatly shortens the discharge distance of the overburden materials from the adjoining open-pit mine, also solves the safety problems such as air leakage and spontaneous combustion of coal caused by fractures in mine subsidence, and brings significant economic and social benefits.