This　study　investigates　the　thermal　conduction　behavior　of　Mg-8Gd-1Er-xZn-1Mn　(x　=　4,　6,　8　wt%)　alloys　with　varying　Zn　content.　The　results　indicate　that　the　as-cast　alloys　contain　only　the　W-phase,　and　its　volume　fraction　increases　with　the　Zn　content　rises.　After　rolling,　the　block-like　W-phase　is　fractured,　and　a　substantial　number　of　fine　W-phase　and　alpha-Mn　phase　precipitates　in　the　GEZM8181　alloy.　The　thermal　conductivity　of　the　as-rolled　GEZM8141,　GEZM8161,　and　GEZM8181　alloys　are　79.6　W/(m　center　dot　K),　112.1　W/(m　center　dot　K),　and　131.0　W/(m　center　dot　K),　respectively.　The　quantitative　analysis　of　the　microstructural　factors　contributing　to　the　reduction　in　thermal　conductivity　reveals　that　solute　atoms　have　the　most　significant　impact　on　thermal　conductivity,　and　their　effect　gradually　weakens　with　increasing　Zn　content.　For　the　deformed　Mg-8Gd-1Er-xZn-1Mn　alloys,　the　factors　contributing　to　the　reduction　in　thermal　conductivity　can　be　ranked　in　the　following　order:　solute　atom　＞　secondary　phase　＞　grain　boundary　＞　dislocation.　This　demonstrates　that　optimizing　the　proportion　of　solute　atoms　and　secondary　phases　in　the　Mg　matrix　is　essential　for　designing　high-thermal-conductivity　magnesium　alloys.　These　findings　provide　valuable　insights　for　understanding　the　thermal　conduction　behavior　of　Mg-RE　series　alloys.