Abstract: The stratigraphic sequence of Lower Paleozoic Weifang Formation and Dongkengkou Formation in southwestern Fujian has long been a problem of controversy. In this paper, the authors studied geochronology of 120 detrital zircon samples from the Lower Paleozoic Weifang Formation and Dongkengkou Formation sedimentary rocks in southwestern Fujian by LA-ICP-MS U-Pb dating, and obtained zircon ages ranging from 506Ma to 3431Ma, with most of the data from 511Ma to 2796Ma, the main peak value 964Ma, a secondary peak value 514Ma, and secondary peak values 813Ma, 1231Ma, 2483Ma. Characteristics of the age spectrum suggest that Weifang Formation was deposited earlier than Dongkengkou Formation. Age of Dongkengkou Formation does not belong to MiddleUpper Cambrian. Lower Paleozoic source with peak value at 964Ma most significantly reflects the Grenville tectonic event. The authors also received peak value age of 514Ma of Pan-African tectonic event. In addition, the authors found Paleoarchean zircon ages record. Important new information is thus provided for the establishment of Lower Paleozoic stratigraphic sequence; source studies.