As　a　new　kind　of　carbon　nanostructured　material,　graphene　and　its　derivatives　have　attracted　extensive　attention　owing　to　their　outstanding　optical　limiting　(OL)　properties.　However,　most　of　the　current　studies　concentrate　on　liquid　matrix.　In　this　work,　we　use　chitosan　(CS)　as　matrix　and　homogeneously　disperse　graphene　oxide　(GO)　into　it　to　prepare　GO-CS　composite　films.　We　comparatively　study　the　different　OL　effects　and　mechanisms　of　GO　in　liquid　and　solid　matrix.　The　results　show　that　GO　presents　stronger　nonlinear　optical　effect　and　weaker　nonlinear　optical　scatter,　which　indicates　that　different　from　carbon　nanotubes,　GO　may　possess　multi　sort　of　nonlinear　optical　effects.　©　Chinese　Physical　Society.