Improving　the　freeze-thaw　resistance　of　geopolymers　is　of　great　significance　to　ensure　their　durability　in　cold　regions.　This　study　presents　an　experimental　investigation　of　optimal　slag　content　for　geopolymer　composites　under　freeze-thaw　cycles　with　different　freezing　temperatures.　Firstly,　five　kinds　of　geopolymer　composites　with　10.0%,　20.0%,　30.0%,　40.0%,　and　50.0%　slag　contents　and　1.0%　fiber　content　were　prepared.　Freeze-thaw　cycle　tests　at　-1.0　celcius,　-20.0　celcius,　and　-40.0　celcius　were　carried　out　for　these　geopolymer　composites　and　their　physical　and　mechanical　properties　after　the　freeze-thaw　cycle　were　tested.　The　results　show　that　the　porosity　of　the　geopolymer　composites　decreases　as　the　slag　content　increases.　Their　mass　loss　ratio　and　strength　loss　ratio　increase　gradually　as　the　freezing　temperature　decreases.　The　mass　loss　ratio　and　strength　loss　ratio　of　geopolymer　composites　after　freeze-thaw　cycles　all　decrease　as　the　slag　content　increases.　Considering　the　physical　and　mechanical　properties　of　geopolymers　after　freeze-thaw　cycles,　the　optimal　slag　contents　are　40.0%　and　50.0%.