The medium-sized Wutubulake iron deposit in the eastern extension of the Altay ore belt within Xinjiang is hosted in the metamorphosed volcaniclastic-sedimentary sequence of the Upper Silurian-Lower Devonian Kangbutiebao Formation. The ore bodies in the ore deposit occur as stratoids or lenses, surrounded by skars minerals. Skarn minerals include garnet, chinopyoxene, scapolite, albite, actinolite, epidote, chlorite, apatite etc. whereas ore minerals are mainly magnetite, with minor pyrite, chalcopyrite, pyrrhotite, molybdentite etc. Field evidence and petrographic observation indicate four stages of metallogenesis, i.e., prograde stage, retrograde stage, sulfide stage and supergene stage. Electron microprobe analyses show that the end member of garnet is mainly andradite, with the calculated end number dominated by andradite (And: 72.89%～84.09%, 78.44% on average), followed by almandite (Alm: 8.23%～12.86%) and grossularite (Gro: 3.47%～14.97%), both of which are less than 20%. The composition of pyroxene is mainly diopside, with a small amount of augite. The end member of diopside is dominated by wollastonite (Wo: 43.48%～45.84%), followed by enstatite (En: 27.02%～34.14%) and ferrosilite (Fs: 18.72%～25.56%). The amphiboles show insignificant compositional variation, mostly being ferrotschermakite. The composition of these skarn minerals suggest that skarn in the Wutubulake iron deposit is calcic skarn, belonging to metasomatic skarn. The epidote is rich in Al and Ca but poor in Fe and Ti, indicating that Fe and Ti were separated out at the same time of the formation of epidote. Electron microprobe analyses show that the composition of magnetite is mainly FeOT (91.17%～93.63%), and most magnetite has similar chondrite_normalized rare earth element distribution patterns and is enriched in light rare earth elements, with an obvious Eu positive anomaly, which is similar to the rare earth element distribution patterns of skarns in this area. The Ni/Co values of magnetite range from 0.15 to 4.29, but most of them are lower than 1.0. All of these characteristics suggest that the formation of magnetite was closely related to the skarns. The above mineralogical characteristics are similar to things of minerals in typical metasomatic skarn iron deposits, implying that the Wutubulake iron deposit is a metasomatic skarn iron deposit. In combination with the geological characteristics, the authors hold that the skarns might have resulted form hydrothermal interaction with metamorphic volcanic and carbonate beds and lenses, and the formation of magnetite was related to the retrogressive metamorphism of the skarns.