The utility model discloses an offline wide-mouth multi-module moulding die for a plastic structural pipe. The offline wide-mouth multi-module moulding die for the plastic structural pipe comprises a front end cover, a rear end cover, a pushing piece, a stationary shaft, a first wide-mouth die set and a second wide-mouth die set, wherein the front end cover and the rear end cover are connected by virtue of the stationary shaft, and the pushing piece is slidably fixed on the stationary shaft; the pushing piece overall is a cone, multiple bevelled edges are distributed on the cone, and a sliding chute is formed in one bevelled edge in adjacent bevelled edges; the first wide-mouth die set comprises multiple first wide-mouth dies which are arranged at intervals, and each first wide-mouth die is provided with bevelled edges which are intersected inward at the two sides; the two ends of each first wide-mouth die are respectively movably arranged on the front end cover and the rear end cover; the second wide-mouth die set comprises multiple second wide-mouth dies which are spaced each other, and each second wide-mouth die is arranged between two adjacent first wide-mouth dies; and volume of each second wide-mouth die is smaller than the volume of each first wide-mouth die. The offline wide-mouth multi-module moulding die for the plastic structural pipe has the beneficial effect that a PVC corrugated pipe online wide-mouth die with simple structure and processing convenience can be provided.