The invention discloses a method for cracking slag and smelting soot of the waste circuit board, belongs to the field of comprehensive recycling of valuable elements from typical soot of waste circuit boards, and particularly relates to a method for cracking slag and smelting soot of the waste circuit board for debromination and comprehensive recovery of copper and zinc. The method includes the following steps of: crushing and sorting, mixture roasting, reinforced leaching, replacement and silver precipitation, sulfuration and copper precipitation, and evaporation crystallization. Compared to traditional recycling technology, the purpose of treating two kinds of solid waste in a coupling mode through one recycling technology is achieved. Through mixed sulfuric acid roasting, the requirement of bromide synergistic removal of the waste circuit board cracking slag and smelting soot is met, and the purpose of selective conversion of copper and zinc is achieved.