Based　on　the　theory　of　limit　equilibrium　of　deformed　body　corresponding　to　the　traditional　theory　of　limit　equilibrium　of　rigid-plastic　body,　the　finite　element　contact　simulation　method　is　presented　for　computations　of　active　earth　pressures　acting　on　L-shaped　retaining　walls　with　reduced　friction　coefficients　of　base　bottoms.　According　to　this　method,　the　computations　of　the　engineering　cases　by　using　the　commercial　non-linear　finite　element　analysis　program,　i.e.,　ABAQUS　are　performed.　The　existence　of　the　second　sliding　surfaces　behind　substantially　planar　retaining　walls,　which　is　once　a　theoretical　supposition,　is　discovered　and　proven　by　the　numerical　simulation　method.　The　positions　of　the　first　and　second　sliding　surfaces　behind　L-shaped　retaining　walls　that　accord　with　the　conditions　of　substantially　planar　retaining　walls　are　revealed　truly.　The　potential　third　sliding　surfaces　in　backfills　behind　L-shaped　retaining　walls　which　do　not　strictly　accord　with　the　conditions　of　substantially　planar　retaining　wall　are　also　discovered.　The　present　method　is　rigorous　in　theory,　and　it　is　shown　by　its　comparisons　with　practical　engineering　cases　that　the　distributions　and　magnitudes　of　active　earth　pressures　acting　on　backs　of　L-shaped　retaining　walls　can　be　obtained　more　accurately　and　reasonably　by　this　method.　It　is　more　reliable　than　Rankine　earth　pressure　theory　which　was　conservative　or　unsafe　for　the　calculations　of　the　factors　of　safety　against　sliding　and　the　factors　of　safety　against　overturning,　respectively.　Meanwhile,　the　present　method　is　of　high　efficiency,　so　it　will　have　a　bright　application　prospect.