The invention discloses a high-temperature melt extrusion 3D printing system. The high-temperature melt extrusion 3D printing system comprises an outer box body, a high-temperature forming chamber, aprinting nozzle assembly and a printing platform assembly, wherein a feeding hole is formed in the upper portion of a high-temperature heat preservation box body of the high-temperature forming chamber, open windows are formed in the lower portions of the left side face and the right side face, the open windows are provided with heat insulation protecting plates which are movably sealed; the printing head assembly comprises a printing head nozzle unit, a feeding unit and a Z-direction moving mechanism; the feeding unit comprises a feeding pipe and a feeding mechanism, wherein one end of the feeding pipe extends into the high-temperature heat preservation box body through the feeding hole, and the feeding pipe and the feeding mechanism are connected with the printing nozzle assembly; the Z-direction moving mechanism is arranged outside the high-temperature heat preservation box body and drives the feeding mechanism and the printing nozzle to move in the direction Z; and the printing platform assembly comprises two sets of X-Y two-dimensional translation mechanisms and a high-temperature printing platform, wherein the X-Y two-dimensional translation mechanisms are symmetrically arranged on the left side and the right side of the heat preservation box, and two ends of the high-temperature printing platform are connected with the X-Y two-dimensional translation mechanisms and are used for supporting a high-temperature-resistant cross beam of the printing platform.