This new methodology utilizes Quality Function Deployment (QFD) with Analytic Hierarchical Process (AHP) together for improving product planning stage, hence, the product development, because this stage precedes the manufacturing stage and is regarded as an important stage in the product development. The proposed methodology consists of two models; namely: (1) Curent QFD Model. (2) Current AHP Model. It was applied practically to demonstrate the models' applicability and suitability, and develop liquid Gas Cylinder Valve produced at Al-Ikhaa General Company (IGC) for Mechanical Industries. "Thus it was possible to find out the critical and important specifications for improving product planning which should be considered in product development". These specifications have high ranking and Scaled Value Technical Ratings (SVTR) of over (50%). SVTR have values as follows: (1) (1.0000) for Pad (H1), then (2) (0.9270) for piston (H4), (3) (0.9195) for gasket (H12), (4) (0.8236) for safety valve (H6), (5) (0.8156) for sealing 1 (H5), (6) (0.6935) for sealing 2 (H9), (7) (0.5441) for installing the regulator with valve (H10) and (8) (0.5220) for spring2 (H7). When applying AHP method, various results were obtained. Based on the final score of Al-Ikhaa Company, where the highest defects value was (45%) was reported in the production processes. Also, values of maintenance dismantling 23%, Product assemblage 12% and maintenance assemblage 9% of the Product values.