To　clarify　asymmetric　mechanical　behaviors　of　the　extruded　Mg-4.58Zn-2.6Gd-0.18Zr　alloy　during　room　temperature　tension　and　compression,　the　evolution　of　microstructure,　texture　and　strain　hardening　rate　were　systematically　investigated　when　loading　along　the　extrusion　direction　(ED).　The　results　found　that　the　asextruded　alloy　exhibited　＜1010＞-＜1120＞　double-peak　fiber　texture,　leading　to　obvious　tension　compression　yield　asymmetry　and　compressive　yield　plateau.　Fiber　texture　kept　stable　and　only　texture　intensity　gradually　decreased　with　the　increasing　tensile　strain,　while　fiber　texture　was　exhausted　due　to　the　extension　twinning　and　＜0001＞　texture　component　was　aggravated　with　the　increasing　compressive　strain.　Moreover,　twinning　parts　within　grains　with　＜1010＞　fiber　texture　was　re-oriented　to　the　c-axis　paralleling　to　the　ED,　and　that　in　＜1120＞　fiber　texture　deviated　about　30　degrees　away　from　the　ED.　This　soft　orientation　would　be　finally　rotated　to　the　＜0001＞　paralleling　to　the　ED　under　the　action　of　basal　slip,　explaining　why　the　＜0001＞　pole　dispersed　at　first　and　then　concentrated　with　the　increasing　compressive　strain.　Three　stages　of　strain　hardening　rate　were　both　observed　for　tensile　and　compressive　tests,　while　increment　of　Stage　II　was　only　observed　under　compression.　Stage　II　in　compression　could　be　further　divided　into　two　parts　with　different　slopes.　Such　phenomenon　was　seldom　reported　in　Mg　alloys,　which　was　caused　by　different　propagation　and　re-orientation　of　extension　twinning　in　double-peak　fiber　texture,　and　weakened　the　effect　of　twin　lamella　segmentation　with　the　increasing　compressive　strain.　Findings　in　this　work　given　us　a　better　understanding　of　asymmetric　tensile-compressive　mechanical　behaviors　of　extruded　Mg　alloys　with　double-peak　fiber　texture.