The invention discloses a comprehensive utilization system and utilization method for waste open pit. An artificial gravity dam is built at the middle part of an open pit, and the pit is divided intoan energy conversion utilization area and an oil storage area adjacent to each other; the artificial gravity dam is internally provided with a drainage pipeline, a hydroelectric power generation equipment and a water suction pump are reasonably distributed in the energy conversion utilization area on one side of the artificial gravity dam in a gathering manner, a potential energy is used for generating electricity, and an electric energy can be converted to the potential energy again through the water suction pump, so that energy conversion and storage in various forms are realized; an oil tank is stored at an oil tank placement stratum below the ground surface of the oil storage area on one side of the artificial gravity dam of the pit, so that alternate rapid input storage and extrusionof water and oil can be realized, full utilization of the open pit is realized, the investment and land resource loss of building an oil storage place on the ground are reduced, and meanwhile, the safety of an oil storage system is improved. The comprehensive utilization system and utilization method are low in cost of required materials, good in operability, small in engineering quantity of wholeconstruction, short in construction period and lower in required cost.