The variation procedure of material components from the original carbon mudstone to the slip band of the landslide in coal measure strata is studied by analysis of chemical constitution, X-ray diffraction and infra-red spectrum absorption, and then the ultimate cause for the distinct difference in mechanical properties under the condition of dry and soakage between the two kinds of related materials is given. Finally, on the basis of the results of grouped quick shear tests on the remolding slip band soil samples, this paper discusses the correlation between moisture content, dry density and the shear strength parameters, and gives the empirical formulas with practical value.