Abstract: In order to find the hidden morphological characteristics of the rock mass in Huyanshan, based on the spatial variation characteristics of the volatilization of the coal seam on the side of the intrusive rock mass, the mechanism of the hidden morphological characteristics of the intruded rock mass in the coal strata can be described. According to the volatile content data of 469 groups of coal seams near Huyanshan rock mass in Xishan Coalfield and the results of previous research, the relationship between the volatile content of coal seam and the distance of the intruding rock mass was studied by making the contour map of the volatile content of the coal seam and the profile diagram of the vertical volatile change direction in the study area of 02^#、 2^#、 6^#, 8^# and 9^# in the study area, and the results showed that: contact metamorphic zone, constant temperature metamorphic zone, dissipative metamorphic zone and normal coal belt appeared on the side of the intrusive rock mass in Huyanshan. The influence belt width of rock mass is about 7 km, of which the width of contact metamorphic zone is within 1 km, the width of constant temperature metamorphic belt is within 4-5 km, and the width of dissipative metamorphic belt is 2-4 km. The hidden form of the intrusive body of Huyanshan in the coal system is a large rock mass, of which there are many small rock plants under the No.9 coal seam, and the influence degree of rock mass baking from top to bottom of the coal seam gradually increases.