The ore-bearing pluton in the Suonaga Pb-Zn-Ag deposit is composed of medium-coarse-grained granite, fine-grained biotite granite and pseudoporphyritic K-feldspar granite. The zircon U-Pb dating results show that the medium-coarse-grained granite was formed at (319.6±4.1) Ma, the fine-grained biotite granite was formed at (172.5 ±1.4) Ma, and the pseudoporphyritic K-feldspar granite was formed at (165.5 ±1.8) Ma. The petrogeochemistry of the three rock bodies is characterized by high K, rich alkali and poor magnesium, so they all belong to calcium-basic, quasi-aluminous to weakly peraluminous and highly-differentiated rocks.