Based on studies of petrology, geochemistry, mineralogical chemistry of biotites, the authors hold that the three composite granitic plutons in the mid-western Nanling Region display two petrogenic models. One is the evolutional model of magmas with different parents, which occurred in the Huashan composite granitic plutons, and the Meihua supplementary granite might have resulted from derivative liquids segregated from fractional crystallization of magmas equivalent to Huashan magmas. The other is the evolutional model of magmas with the same parent, which occurred in the Jinjiling and Dadongshan composite granitic plutons. Their supplementary bodies, namely Pangxiemu granite and Zhutishi granite, resulted from the condensation of the residual magmas, and the two residual magma bodies were generated by fractional crystallization of the parental magmas of the Jinjiling and Dadongshan main bodies respectively. Two kinds of evolutional models of the supplementary granites may suggest the different genetic mechanisms of magmas of their main bodies.