Abstract: Thematic mapping is a problem-driven and demand-driven update of comprehensive geological mapping. As a new exploration about ways of geological survey work, it is of vital significance not only for realizing the integration of geological survey and scientific research but also for the sustainable development of geological mapping work. So it is essential to carry out thematic geological mapping. Up to date, there is no design specification for thematic geological mapping, and the methods need to be piloted, explored and innovated. This paper discusses some thoughts and methods about mineral geological mapping for porphyry-skarn ore deposits. With Beiya area of Yunnan Province as an example, the authors describe mineral geological mapping in detail. Some encountered problems and their solution are also discussed.