Abstract: The Mo-Ni deposits in Zunyi-Nayong area of Guizhou Province occur mainly in the black shale series of Lower Cambrian Niutitang formation, with ores in clasts, specks and micro-veins. The Mo-Ni-bearing fragments represent clear orientation and undulate distribution. The upper part of the Mo-Ni bed is composed of brown fine fragments with pyrite and clay. At the lower part, the ore bed consists of Mo-Ni-bearing clasts and clay. The sizes of the fragments get finer from bottom to top of the bed. Macrocrystalline limestone is developed under the Mo-Ni bed. The characteristics of the Mo-Ni bed shows that the Mo-Ni deposits in the Niutitang formation is formed by hydrothermal eruption sedimentation.