Abstract: The paper mainly discusses the relationship between sulphur content in coal seam and the thickness of underlying sand body of 20 coal seams in Huoxi, Xishan, Pingshuo, Dtong, Qinshui coalfields of Henan province. By detailed analysis of superimposed position of isogram of sulphur content in coal seam and isopach of the thickness of underlying sand body, it is revealed that the peak value area of sulphur content is often situated on the areas where underlying sand bodies are thinner or pinch out. In other words, they are arranged in a staggered position. Among the 188 peak value areas of sulphur content from 20 pairs of isogram maps, 8 are located in superimposed position with the peak value areas of underlying sand body in most part (4.26%); 10 are partly located in superimposed position (5.32%); whereas 121 are located on the are a of thinner underlying sand body (64.36%); and 49 are located on the pinch out area of the underlying sand body(26.06). It shows that the numbers of peak value areas of sulphur content, which are located on the thinner and pinch out parts of the underlying sand body make up 90.42%, so the staggered position between these two peak value areas is a general character with a reliability of 90%. Mean while, it is revealed that the isogram lines of the lines of peak value areas of sulphur content and underlying sand body often have concordant outlines, they are often in mosaic or parallel patterns. The control factor of these kinds of phenomena is the difference in the base relief of coal-forming peat swamp determined by underlying sand body. Where the underlying sand body is thicker, the base relief is higher. In the lower area, in comparison with the higher area, commonly existed more underground or surface streams, which carried more fine suspending clays absorbing iron ions and calcium sulface that would be reduced later and transformed to more pyrite. As a result of this process, the coal seam formed in the lower area contains much more slphur than that formed in the higher area. This relationship can be used for prediction and searching for the coal area with lower sculphur content, and predicting the alternate tendency of coal seam’s sulphur content in the process of coalfield exploration,