Here, "barium slag" refers to a solid by-product or waste slag generated and discharged from raw-material reaction, extraction or purification steps during the production of barium salts, barium chemical products or related inorganic chemicals, typically containing barium sulfate, barium carbonate, barium oxide and small amounts of unreacted raw materials and impurities. After such barium slag has lost its original process function or been discarded, following stabilization treatment, sorting and comprehensive utilization it can be used as a building-material filler, chemical raw material or for recovering the barium resource therein, achieving resource recovery.