The invention discloses a potassium-extracting and processing process for low-sulfur potassium mixed salt. The potassium-extracting and processing process comprises the following steps: (1) mixing andgrinding potassium mixed salt ores with C-point mother liquor, and adding fresh water or unsaturated mother liquor to stir to complete conversion after grinding the ores; (2) regulating converted orepulp by utilizing C-point mother liquor, and performing aeration flotation after adding a collecting agent 601 to regulate ore pulp; (3) performing solid-liquid separation on concentrate foam and tailings pulp; (4) regulating the tailings pulp by utilizing D-point mother liquor, and adding a collecting agent CA-806; (5) transferring the regulated ore pulp to a flotation machine to perform potassium chloride flotation through a flotation process of roughing, refining and scavenging, and returning refined middling and scavenged concentrate to roughing to form a flotation closed loop; and (6) performing solid-liquid separation on the refined foams and scavenged tailings, thereby obtaining potassium chloride flotation concentration and final tailings, performing a washing process on concentrate, and leading the final tailings to a tailings warehouse. The potassium-extracting and processing process is simple in process, is good in product quality and is high in resource utilization rate.