Objectives: The Early Paleozoic Kuanping granite pluton in Danfeng area have important geological significance for constraining the tectonic evolution of the Qinling Mountains. Kuanping granite pluton is composed by gneissic biotite monzogranite and porphyraceous biotite granite.  Methods: Based on the field work, through the microscope observation, the whole rock chemical analysis, the ziron LAICP MS UPb dating of the gneissic biotite monzogranite and porphyraceous biotite monzogranite. Results: The gneissic biotite monzogranite and porphyraceous biotite monzogranite have ages of 448.3 4.5Ma and 421.4 2.5Ma respectively. The gneissic biotite monzogranite display high SiO2 and (Na2O+K2O) contents, they belong to metaluminous and highK calcalkaline series, it is considered to be formed by fluxing melting of plagioclasepoor pelitic rocks in middle—upper crust. The porphyraceous biotite granite is peraluminous, they are considered to be formed by dehydration melting of metagerywacks or granitic gnesis in middle—lower crust.  Conclusions:The geochemical evolution of the Paleozoic granites in the northern Qinling from 450 to 420Ma reveals a tectonic evolution from syncollisional to postcollisional process.