The Danxia Group in Jinjiling area of north Guangdong is mainly composed of fluvial facies calciferous sandstone.On the basis of grain size analysis and artificial placer mineral analysis, four detrital minerals, i.e, quartz,feldspar,tourmaline and zircon were studied under a scanning electron microscope, and it is thus discovered that their surface textures are much more comlilex than the surface textures of similar minerals from any modern coastal and fluvial arenaceous sediments the authors have ever studied. The reason is that the surface of detrital minerals in ancient sandstone not only underwent transformation in the process of weathering, trapsportation and sedimentation like what detrital minerals are experiencing in modern rivers or coastal areas, but also suffered superimposition of further transformation during diagenesis. The composition of intergranular liquid and the change in temperature and in pH value under the diagenetic conditibns played an important role in the formation of surface textures of minerals. It is therefore obvious that the various characteristics of surface textures of minerals are related not only to mineral behaviors but also to the action and influence of the media in the diagenetic environment. A comparison of surface textures of various minerals shows that, in addition to the physical and chemical properties of minerals, the temperatures and pH values of the media in the diagenetic environment are also important factors affecting the formation of surface textures of minerals, with the main reaction being dissolution.The degree of transformation of the four minerals is in decreasing order of tourmaline-feldspar-quartz-zircon, which is not qcite consistent with the sequence of stability of these minerals.