Disclosed is an automatic sofa assembly production line. A sofa comprises a base, a plurality of evenly distributed supporting holes are formed in the back end of the base, supporting springs are arranged in the supporting holes, and a seat cushion is arranged between each two adjacent supporting springs. The automatic sofa assembly production line comprises a first conveying mechanism, a mounting mechanism, a second conveying mechanism, an annular conveying mechanism and a press-down mechanism, wherein the first conveying mechanism, the mounting mechanism and the second conveying mechanism are arranged linearly sequentially, the annular conveying mechanism is arranged above the first conveying mechanism, and the press-down mechanism is positioned above the annular conveying mechanism. During working, the base is disposed on a first conveying belt and conveyed to a fixed position below an annular conveying belt, and the supporting springs are pressed to the supporting holes of the base through a press plate; then the base is conveyed to a workbench, the seat cushion is disposed between each two adjacent supporting springs through a manipulator and is conveyed to a second conveying belt through descent of a top plate prior to subsequent processing. The automatic sofa assembly production line is simple in structure, capable of improving working efficiency and saving in labor.