The Xiaohulishan molybdenum deposit is a medium-size concealed porphyry molybdenum deposit recently discovered in Beishan area, Inner Mongolia. Disseminated, starry and veinlet mineralizations are hosted in fine-grained granite of the marginal facies zone and fine-middle grained porphyritic granite of the transitional facies zone. Metallic minerals are composed mainly of molybdenite and pyrite, with minor amounts of sphalerite, stannite, galena, bismuthinite and magnetite.