A prefabricated steel-wood composite joint, comprising square pipe columns, steel-wood composite beams, and a beam-column connecting assembly for connecting the square pipe columns and the steel-wood composite beams, wherein: each said square pipe column comprises connecting corner columns and connecting side plates, wherein the connecting corner columns are steel columns, the connecting side plates are wood plates, and the square pipe column is of a hollow pipe column structure formed by splicing the connecting corner columns and the connecting side plates; each said steel-wood composite beam comprises a top flange, a bottom flange and wood webs for connecting the top flange and the bottom flange, wherein the top flange and the bottom flange are arranged in parallel and are both steel structures having flange insertion slots formed in inner sides, flange insertion heads matched with the flange insertion slots are formed in top and bottom sides of the wood webs, the wood webs are arranged between the top flange and the bottom flange and are perpendicular to the top flange and the bottom flange, and each said wood web has an end flush with side faces of the top and bottom flanges and an end recessed in the top and bottom flanges and provided with a stepped connecting head; and the beam-column connecting assembly is a central column connecting assembly or a corner column connecting assembly, is used for connecting the square pipe columns and the steel-wood composite beams, and comprises a square solid wood column matched with the square pipe columns in inner diameter, square wood beams are arranged on side faces of the square solid wood column, connecting slots matched with the connecting heads are formed in ends of the square wood beams, and the square pipe columns and the steel-wood composite beams are connected through the square solid wood column and the square wood beams. each said square pipe column comprises connecting corner columns and connecting side plates, wherein the connecting corner columns are steel columns, the connecting side plates are wood plates, and the square pipe column is of a hollow pipe column structure formed by splicing the connecting corner columns and the connecting side plates; each said steel-wood composite beam comprises a top flange, a bottom flange and wood webs for connecting the top flange and the bottom flange, wherein the top flange and the bottom flange are arranged in parallel and are both steel structures having flange insertion slots formed in inner sides, flange insertion heads matched with the flange insertion slots are formed in top and bottom sides of the wood webs, the wood webs are arranged between the top flange and the bottom flange and are perpendicular to the top flange and the bottom flange, and each said wood web has an end flush with side faces of the top and bottom flanges and an end recessed in the top and bottom flanges and provided with a stepped connecting head; and the beam-column connecting assembly is a central column connecting assembly or a corner column connecting assembly, is used for connecting the square pipe columns and the steel-wood composite beams, and comprises a square solid wood column matched with the square pipe columns in inner diameter, square wood beams are arranged on side faces of the square solid wood column, connecting slots matched with the connecting heads are formed in ends of the square wood beams, and the square pipe columns and the steel-wood composite beams are connected through the square solid wood column and the square wood beams.