Systematic geochronological study on the petrogenetic and metallogenic ages of the Machangqing porphyry-type copper-molybdenum-gold orefield,western Yunnan Province has been discussed in this paper. The research reflect that theⅡperiod magmatic combination whose emplacement age is from 33 to 36 Ma, consisting of syenite porphyry+monzonite porphyry+granitic porphyry+ porphyritic granite, is the ore-forming geological body and supplies materials, fluid and dynamic for copper-molybdenum-gold mineralization. The porphyry-type copper-molybdenum mineralization whose age is 35.8 Ma, Luandongshan skarn-type gold mineralization and Rentouqing tectonite-type gold mineralization form at the early-middle stage of Ⅱ-period magma activity.