A technique for preventing fiber breakage was studied during fabrication of PP-based green composite pellets with bamboo short fibers. The residual fiber length in BFRPP pellets fabricated by using the side feeder on a twin-screw extruder was longer than that of conventional products. Improvement of residual fiber length in BFRPP did not affect the tensile properties of injection-molded samples. However, high tensile strength was observed when the fiber aspect ratio was improved. The residual fiber length and fiber aspect ratio in BFRPP pellets were strongly affected by feed position of the materials. This paper shows that the appropriate feed position of both materials significantly increases the residual fiber length and aspect ratio in BFRPP pellets.