Based　on　the　sliding　plane　hypothesis　of　Coulumb　earth　pressure　theory,　the　analytical　solution　of　active　earth　pressure　acting　on　retaining　walls　was　deduced　by　using　the　thin　layer　element　method,　considering　the　complicated　circumstances　that　the　backfill　was　soil　with　cohesion　and　friction　angle,　the　back　of　retaining　walls　and　the　ground　surface　of　backfill　were　both　inclined,　the　frictional　and　adhesive　forces　existed　on　interface　between　retaining　walls　and　backfill,　the　tension　crack　appeared　at　the　shallow　part　of　backfill　and　even　continuous　surcharge　load　acted　on　the　ground　surface　of　backfill.　The　analytical　solution　was　applicable　to　the　complicated　conditions　of　cohesive　soils　and　non-cohesive　soils.　Meanwhile　it　was　proven　that　the　prevailing　classical　Rankine　and　Coulumb　earth　pressures　were　two　special　examples　simplified　under　the　condition　of　their　assumptions,　respectively.　It　was　shown　by　calculations　of　3　engineering　cases　that　the　active　earth　pressure　distributions　computed　by　the　deduced　formula　agreed　well　with　the　measured　non-linear　ones,　indicating　that　the　analytical　solution　was　reliable　to　be　used　to　calculate　the　active　earth　pressure　in　engineering　projects.