Abstract: The invention relates to a method for manufacturing a blade made of composite material extending in a main elongation direction, the composite material of said blade comprising a fiber reinforcement densified by a matrix, the method comprising the following steps: a step of weaving warp yarns and weft yarns to produce a fiber preform, the fiber preform comprising at least one warp yarn adapted to form in the matrix at least one first portion of a channel, said portion of length of the warp yarn being directed according to the main elongation direction of the blade and opening at the root of the blade, the first channel portion formed in the matrix by said portion of length of warp yarn constituting at least one first portion of the internal airflow channel; a step of forming the fiber preform so as to produce a blade preform and densifying said blade preform; characterized in that the weaving step comprises placing at least one second portion of yarn adapted to form in the matrix a second portion of a cha