Composite materials, which are both costly and harmful to the environment, are increasingly being used. A polymer matrix and reinforcement from natural fibres composition of the composite known as a “bio-composite”. Traditional non-renewable reinforcing elements are replaced with natural fibre resources. In this use of the vacuum-assisted resin infusion (VARI) technique, organic fibres such as hemp (H) and flax (F) are employed to produce composites. This study employed the Taguchi technique with L27 as the orthogonal array (OA) to determine the optimal conditions for composite material natural fibre reinforcement production. To identify the best optimal value, response surface methodology (RSM) is used with Grey relational analysis with principal component analysis (GRA—PCA) to get the optimal solutions. Different fibre types (H, F, HF), NaOH concentrations (5%, 10%, 15%), water absorption times (7, 14, 21 h), and concentrations of NaOH were all considered. According to the study’s findings, combining RSM and GRA-PCA to optimize the material production parameters yielded A3B2C1 with an optimum Impact strength (IS) of 0.253 J/ mm2, while A2B1C3 yielded Flexural Strength (FS) of 95.7950 MPa.