The Shipingchuan Kfeldspar granite is situated in south—central volcanic belt of southeastern Zhejiang Province. LA-ICPMS zircon UPb dating yields a weighted mean 206Pb/238U age of 102.5±1.2 Ma （MSDW=2.1）for the Shipingchuan granite intrusion，implying its end of early Cretaceous crystallization time. Petrography and chemical compositions show that it belongs to highK calcalkaline series characterized by high silicon，enriched in kalium and aluminum but depleted in iron，magnesium，phosphorus and titanium.SiO2 and K2O contents range from 74.79% to 77.79% and 4.26% to 7.97% respectively. A/CNK values vary from 0.98 to 1.10，indicating a metaluminous to weakly peraluminous character. The rocks are enriched in Rb，Th，U and K，but depleted in Sr，Ba，Nb，P and Ti. REEs are characterized by intermediate negative Eu anomalies with Eu/Eu* =0.33~0.50 and exhibit rightdipping “V” patterns with LREE enrichment. \[n（87Sr）/n（86Sr）\]iandεNd（t）values （t=102.5Ma）of the Shipingchuan intrusion range from 0.70801 to 0.71012 and -8.76 to -8.63 respectively，showing the intrusion is the result of mixing by crustal and mantle materials.Mineralogy and geochemistry suggest that the Shipingchuan Kfeldspar granite intrusion is a highly fractionated Itype granite. Trace elements features display that the pluton was a postcollisional granite and formed in an extensional tectonic setting in the end of early Cretaceous. These results indicate the Shipingchuan granite is related to backarc extension due to high angle subduction of the paleoPacific plate，caused by northward movement of Indian plate.