Abstract: Using the compactness of sandy pebble as main parameter，static experimental study on the axialcompressive mechanical property of ten sandy-pebble-filled thin-walled square steel tubular columns，was carried outto analyze comparatively the load-carrying capacity，the load-strain curves，failure characteristics and mechanism ofdifferent test specimens． The experimental results indicate that the load-carrying capacities of empty and lowcompactnesssandy-pebble-filled thin-walled square steel tubular column were low，local buckling of tube walloccurred prior to steel yielding，resulting in steel performance failing to get into full play． Compared with square steeltubular stub columns that mentioned above，the co-action of the higher-compactness sandy pebble and tube wall caneffectively delay the local bucking of steel tube wall and enhance greatly the ultimate load-carrying capacity andimprove the global stability of the columns． And whats more，this new type of composite column has good repeatableutilization，as well as economic and environmental characteristics．