Abstract: The early Yanshanian granites emplaced in early Late Jurassic in the Miao’ershan area, southwestern Hunan Province, were mainly intruded in the Caledonian and Indosinian granites and were mainly composed of fine grain and medium to coarse grain porphyritic biotite monzogranites with minor fine grain dimicaceous monzogranites. The rocks are of high silicon (SiO₂=76.02%～80.26%), moderate aluminium (Al₂O₃=10.94%～12.88%), potassium (K₂O=3.42%～5.34%), total alkali (Na₂O+K₂O=5.37%～8.22%) and high ASI values (1.04～1.31, 1.14 on average), showing features of the ferric, calc-alkaline perluminous granitoids. On the PM-normalized incompatible elements spiderdiagram, significant Ba, Sr, P and Ti trough and Rb, (Th+U+K), (La+Ce), Nd, (Zr+Hf+Sm) and (Y+Yb+Lu) humps are observed. The rocks have lower total REE content(Σ REE = 122.9～175.4μg/g), slightly enrichment of LREE ((La/Yb)_N= 2.55～3.79) and pronounced negative Eu anomaly(δEu = 0.07～0.22). As for isotope, they have I_Sr values of 0.99007 and 1.15860 , ε Nd(t) values of -9.20 and -8.80 and t_2DM ages of ~1.7 Ga. The C/MF-A/MF diagram indicates that the granites were derived from metamorphic mudstones and clastic rocks , Al₂O₃/TiO₂ values of some strong perluminous granite samples are less than 100. All above geochemical characteristics reveal their S-type signatures and suggest that the granites were derived from partial melting of acid rocks of middle-upper crust with participation of mantle materials. Multiple oxide- and trace element-diagrams for discrimination of structural environment and regional tectonic geology show that the granites were formed in a post-orogenic tectonic setting . The forming of magma was related with the former thickening of crust in Middle Jurassic and the up-welling and heat transference of asthenosphere mantle.