Many red chert blocks and some irregular stripped manganese-oxide aggregates and crusts are developed in the laterite on the top of the Santaishan peridotites, western Yunnan. Those cherts and manganese nodulars are unlike the marine facies ones in shape, chemical compositions and mineral assemblage. Those dark manganese-oxide aggregates and crusts can be classified as ferri-manganese and cobalt-manganese oxides. The energy spectrum analytical results show the ferri-manganese oxides are complicated and nonuniform in their chemical compositions, with main Mn and Fe and minor Al, Co, Ni, K and Ba elements. The separation degree between Mn and Fe elements is low with Mn/Fe ratios of 0.1~12.6. The cobalt-manganese oxides consist of main Mn, Co, Al, Ni and minor K, Ca and Si, showing high separation degree between Mn and Fe. X-ray powder diffraction analyses show that the ferri-manganese oxides occur as hollandite in crystal structure, and coexist with cryptocrystalline hematite, goethite and clay minerals, having capability of enrichment in Al, K, Ba, Co and Ni elements. The cobalt-manganese oxides is with lithiophorite crystal structure, and is associated with cryptocrystalline hematites and cherts, having capability of enrichment strongly in Co, Al and middle in Ni elements. Based on the methods of energy spectrum, microprobe, X-ray powder diffraction, and whole rock chemical analyses, we conclude that those manganese-oxide aggregates and crusts are generated in the supergene conditions of long-lasting leaching by atmospheric precipitation, acidification and redox on the peridotites, where Ca and Mg in the silicate minerals are lost and Si, Fe and Al are residual. Silicic acid was retained and altered to cherts due to poor drainage condition. Iron- and manganese-oxide gels were precipitated as aggregates and crusts under the alternation of wetting and drying climates. The supergenesis has transformed the peridotites to Fe, Al, Ni, Co, Cr, Mn, Sc and Y enriched laterite with potential economic values.