The　microstructure　evolution　and　strengthening　mechanisms　of　Mg-10Gd-1Er-1Zn-0.6Zr　(wt.%)　alloy　were　focused　in　the　view　of　the　size　parameters　and　volume　fraction　(f(p))　of　dual　phases　(long　period　stacking　ordered　(LPSO)　structures　and　beta＇　precipitates).　Results　show　that　two　types　of　LPSO　phases　with　different　morphologies　formed,　and　the　morphology　and　size　of　both　LPSO　phases　varied　with　the　solution　conditions.　However,　the　volume　fraction　decreased　monotonously　with　increasing　solution　temperature,　which　in　turn　raised　the　volume　fraction　of　beta＇　phase　during　aging.　The　alloy　exhibited　an　ultimate　tensile　strength　of　352　MPa,　a　yield　strength　of　271　MPa,　and　an　elongation　of　3.5%　after　solution　treatment　at　500　degrees　C　for　12　h　and　aging　at　200　degrees　C　for　114　h.　In　contrast　to　the　LPSO　phase,　the　beta＇　phase　seems　to　play　a　more　important　role　in　enhancing　the　yield　strength,　and　consequently,　a　decreased　f(LPSO)/f(beta＇),　ratio　results　in　an　increased　yield　strength.