Recently, many medium- and large- scale fluorite deposits were identified in the Zhejiang Province. However, research on the metallogenic rock mass is still relatively scarce, limiting an understanding of regional mineralization. In this paper, we report new zircon U- Pb geochronologic and whole- rock major and trace element data, for the Xiaoxuwu and Wufangli granites of the Tongli area in Northwest Zhejiang. The zircon U- Pb dating yielded magmatic crystallization ages of 145~140 Ma and 135 Ma for the Xiaoxuwu granodiorites and the Wufangli fine- grained monzogranites, respectively. These new age data indicate that the Tongli plutons were emplaced in the early Early Cretaceous, coeval with the regional late Mesozoic magmatism. Geochemically, the samples can be divided into two groups of calc- alkaline I- type and highly fractionated I- type granites. All of these samples have high SiO2 and Al2O3 contents, but low Fe2O3 and MgO contents, and belong chemically to metaluminous- peraluminous series. Furthermore, the Xiaoxuwu granodiorites are enriched in light rare earth elements and large ion lithophile elements but depleted in heavy rare earth elements and high field strength elements while the Wufangli fine- grained monzogranites are characterized by middle rare earth elements. Our research indicated that the Xiaoxuwu I- type granites were derived by partial melting of meta- igneous lower- crustal source while the Wufangli highly fractionated I- type granites underwent extensive fractional crystallization in the shallow magma chamber. Combined with the oceanward migration of late Mesozoic magmatic activity, we believe the slab rollback during oceanic subduction of paleo- Pacific is a reasonable explanation for the magmatism in the Tongli area.