Although logging data of each drilling hole only presents its’ geological section, there must be internal connections among drilling holes. Studies and analysis of internal connections among every drilling hole are helpful to recourse coal seams and strata, study plain change rules of coal layers, and to deduce geological structure between drilling holes. Therefore, conventional digital logging curves such as D3C, HGG and HG are used for comparative study of East Yunnan coal seam (C2 1, C7, C9, C11, C13, C16, C23, C24, etc.). It was found that anomalous amplitude, form and distinctive mark have remarkable effect on coal seam correlation.