Based on process mineralogical study of a low-grade Ag-Pb-Zn-CaF2 sulphide ore in SW China, the occurrence of Pb and Zn, the distribution of silver minerals and their relationships with other minerals are determined in details, which provides scientific reference for the forthcoming flotation process. The mineralogical results show that four silver minerals are determined, which aftonite occupies the most. Unlike other siliver minerals which are included in lead minerals and could be enriched in lead concentrates, aftonite could be liberated as an independent mineral after grinding and may be lost in the tailings, so key factors influencing the flotation of aftonite, such as pH value of pulp, effective col ectors, etc., should be handled reasonably to get it better recovered. Besides, note that 2.1% calcite, 6.85% dolomite, which have close flotabilities to fluorite, wil also be enriched affecting the quality of the fluorite concentrates. Thus, how to depress the quartz and the calcic gangue minerals during fluorite flotation is also the key factor of the whole process.