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In Eocene Huadian Formation in Huadian Basin��the fan delta can be mainly divided into the following microfacies: debris flow��overwater distributary channel��underwater distributary channel��river mouth bar and sheet sand�� The microfacies of the underwater fan in the Huadian Formation are mainly braided channel and far source turbidite�� The sediments of the fan delta mainly show grain-supported structure�� According to the bottom-up sequential pattern of sheet sand��river mouth bar��underwater distributary channel��overwater distributary channel and debris flow��the grain size and standard deviation are increasing; the sharpnesses of frequency curves are decreasing; the shapes of the probability cumulative curves change from higher-high slope two segments through medium- low slope two segments to slightly upward convex curvilinear style�� The microfacies show the characteristics of reverse grain size order��sorting degrees decreasing��contents of matrix and water body energies increasing in ascending order�� The sediments of the underwater fan show matrix-supported structure�� According to the bottom-up sequential pattern of far source turbidite and braided channel��the grain sizes and standard deviations are increasing; the sharpnesses of frequency curves are decreasing; the shapes of the probability cumulative curves mainly change from higher slope one segment to lower slope one segment or slightly upward convex curvilinear style�� These changes reflect that from far source turbidite to braided channel��grain sizes become coarse��sorting becomes poorer�� contents of matrix and water body energies are increasing�� The CM diagram of the fan delta in the study area has S-shap��which mainly corresponds to traction current deposits; the CM diagram of underwater fan shows longband paralleling to the C = M line��which corresponds to gravity flow deposit��