With　the　different　Er　additions,　the　tensile　properties　of　under-aged　1420　alloy　at　different　directions　are　tested,　and　the　deformation　texture　and　microstructure　of　the　alloy　are　observed,　the　effects　and　mechanisms　of　Er　on　the　anisotropy　of　mechanical　properties　of　1420　alloy　are　studied.　The　results　show　that　with　Er　addition　increased,　the　anisotropy　of　mechanical　properties　of　1420　alloy　is　remarkably　enhanced,　which　mainly　result　from　that　Er　can　greatly　intensify　the　texture　of　B{011}　less　than　or　equal　211＞,　facilitate　the　precipitation　and　growth　of　δ＇　phase,　and　further　cause　the　larger　size　and　higher　volume　fraction　of　δ＇　phase.