Graphene-reinforced　aluminum　matrix　composites　(GRAMCs)　attract　great　interest　in　industries　due　to　their　high　performance　potential.　High-temperature　processes　such　as　sintering　and　aging　are　usually　applied　during　the　preparation　of　GRAMCs,　leading　to　grain　coarsening　that　significantly　influences　its　properties.　In　this　work,　a　modified　3D　Monte　Carlo　Potts　model　was　proposed　to　investigate　the　effect　of　content　and　size　of　graphene　on　the　grain　evolution　during　the　heat　treatment　of　GRAMCs.　Grain　growth　with　graphene　contents　from　0.5　wt.%　to　4.5　wt.%　and　sizes　from　5　mu　m　to　15　mu　m　were　simulated.　The　grain　growth　process,　final　grain　size　and　morphology　of　the　microstructure　were　predicted.　The　results　indicated　that　both　the　content　and　size　of　the　reinforcements　had　an　impact　on　the　grain　evolution.　The　pinning　effect　of　grain　size　can　be　enhanced　by　increasing　the　content　and　decreasing　the　size　of　graphene.　Agglomeration　and　self-contacting　phenomena　of　the　graphene　arose　obviously　when　the　contents　and　sizes　were　relatively　high.　The　average　grain　size　decreased　by　48.77%　when　the　content　increased　from　0.5　wt.%　to　4.5　wt.%.　The　proposed　method　and　predicted　regulations　can　provide　a　reference　for　the　design　and　fabrication　of　GRAMCs.