Abstract: Based on coal geological exploration data of Dafeng mine, the paper used Surfer and AutoCAD to draw the contour maps of ash, volatile, sulfur and calorific value of the lower seam No.5, summed up the law of coal quality variation of seam No.5. The results show that the ash and the carorific value change the most obviously in the center of the mine; ash content increaes gradually from the edge to the center of the mine and reaches the maximum in the center, carorific value decreases gradually and is the lowest in the center.The coal quality is relatively poor in the center and slightly better in the east and the west near mine boundary. The delineated scope of anthracite provided the basis for reasonable mining of lower seam No.5 and regulation and control of the quality of coal product in Dafeng mine.