Based　on　the　strength　criterion　under　plane　strain　condition　and　Rankine＇s　theory,　a　simplified　method　for　determination　of　limit　earth　pressure　is　proposed.　The　principal　stress　in　the　plane　strain　direction,　which　can　be　determined　under　the　rigidity-plasticity　assumption　using　static　earth　pressure　coefficient,　is　the　intermediate　principal　stress　under　the　limit　equilibrium　condition.　The　relationship　between　major　and　minor　principal　stresses　is　obtained　based　on　the　strength　criterion.　Then　the　earth　pressure　coefficient　can　be　determined.　Although　the　proposed　method　is　as　simple　as　that　of　the　Rankine＇s　theory,　it　can　obtain　more　reasonable　calculation　results,　and　accordingly　improve　the　design　methodology　yielding　output　more　economically.　The　results　also　show　that　the　difference　between　the　proposed　method　and　the　Rankine＇s　theory　is　enlarged　along　with　the　increase　of　the　friction　angle　of　the　material.　The　validity　of　this　method　is　confirmed　by　observed　data　from　the　practical　foundation　engineering.　Compared　with　the　Rankine＇s　theory,　the　proposed　method　can　be　more　rationally　used　in　soil-retaining　structure　designing.