Access　control　is　an　important　measure　for　the　protection　of　information　and　system　resources　to　prevent　illegitimate　users　from　getting　access　to　protected　objects　and　legitimate　users　from　attempting　to　access　the　objects　in　ways　that　exceed　what　they　are　allowed.　The　restriction　placed　on　access　from　a　subject　to　an　object　is　determined　by　the　access　policy.　With　the　rapid　development　of　cloud　computing,　cloud　security　has　increasingly　become　a　common　concern　and　should　be　dealt　with　seriously.　In　this　paper,　we　survey　access　control　models　and　policies　in　different　application　scenarios,　especially　for　cloud　computing,　by　following　the　development　of　the　internet　as　the　main　line　and　by　examining　different　network　environments　and　user　requirements.　Our　focus　in　the　survey　is　on　the　relationships　among　different　models　and　technologies　along　with　the　application　scenarios　as　well　as　the　pros　and　cons　of　each　model.　Special　attention　will　be　placed　on　access　control　for　cloud　computing,　which　is　reflected　in　the　summaries　of　the　access　control　models　and　methods.　We　also　identify　some　emerging　issues　of　access　control　and　point　out　some　future　research　directions　for　cloud　computing.