The intermediate-acid intrusive rocks exposed in the West Junggar, southwestern segment of the Central Asian Orogenic Belt, are mainly metaluminous to weakly peraluminous I-type and A-type granites. This study presents petrological, zircon U-Pb geochronological and in-situ Hf isotopic, whole-rock geochemical data of the newly discovered primary-muscovite-bearing strongly peraluminous granites in the Azhaken area. Petrographic observation results show that the strong peraluminous granites are mainly composed of muscovite monzonitic granite porphyry, two-mica monzonitic granite, muscovite granite and granite porphyry. LA-ICP-MS zircon U-Pb dating reveals middle Late Carboniferous magmatism with age of 309.1±3.8 Ma, later than metaluminous I-type granites (322~310 Ma) but slightly earlier than weakly peraluminous A-type granites (307~294 Ma) in the region. It is geochemically characterized by enriched silicon, aluminum, but depleted calcium, ferrum and magnesium, and possesses high total alkali content and aluminum saturation index (A/CNK=1.06~1.24, 1.14 in average), and also enrichment in Ba, Rb, K, Th, U with pronouneed negative Nb, Ta and Ti anomalies. In addition, it is characterized by corundum content of 0.85%~2.83% (1.79% in average) and absence of diopside showed through CIPW standard mineral calculation, indicating that they are strongly peraluminous high-K calc-alkaline S-type granite. In-situ zircon Hf isotope analyses show that these granites have high positive εHf(t) values (+10.8~+15.6) and very young two-stage Hf model ages of 326~633 Ma, suggesting that the magma was sourced from juvenile crust originated from depleted mantle. In association with previous analysis, it is proposed that the newly discovered middle Late Carboniferous strongly peraluminous S-type granites were probably originated from muscovite dehydration melting of metapelites under the water-absent condition during the initial transformation from extrusion to extension regime in the rapid collage process of subduction accretion bodies under the background of northwestward subduction of the Junggar oceanic crust.