The invention relates to a method for molding a fibre reinforced composite material drawing and extruding thin-wall section material. A guide mechanism is arranged in a mould port; the rear end of a first guide device is embedded into a square hole of a second guide device; an inner layer of a sternum of the section material adopts a paving layer of fibre fabric in any direction; two fabric layers of an outer layer contain 0 degree paving layers; the upper wing edge and the lower wing edge of the section adopt fibre fabric or unidirectional fibre; an inner layer of the sternum runs through a middle hole of the first guide device; two layers of the outer layer of the sternum run through an upper side hole and a lower side hole respectively; the upper wing edge and the lower wing edge of the section material run through two sides of the second guide device; and the section material is subjected to wire threading, gum dipping and heating and molding. The method overcomes the disadvantages that in the prior art the section material has low vertical and transverse shearing strength and can be only distributed along longitudinal unidirectional direction. The method substantially improves the strength of the fibre reinforced composite material drawing and extruding section material in non-principal direction; the section material is subjected to once curing and molding in a drawing and extruding production line and has excellent apparent performance and high-efficiency production speed; and the cost is not obviously improved.