Zircon SHRIMP U-Pb dating of Dachong granodoirite in Fozichong deposit, Guangxi, is conducted in this paper, yielding an age of (258.2±3.2) Ma 9 5% confidence MSWD=0.59.The result shows Dachong stock intruded at shallow place in Hecynian, not late Yanshanian constrainted by former researchers. Compiled with regional metallogenic rule of “no Hecynian mineralization” and geological characteristics of this deposit, the authors support metallogenic granite is not Dachong granodoiritic stock, but Yanshanian granitic porphyry dike swarm. The Yanshanian granitic porphyry together with Pb, Zn mineralization, were obvious controlled by Niuwei fault system.