Fly ash has gained the widespread attention of researchers in aluminum matrix composite (AMC) production as reinforcement to enhance the properties of AMCs and reduce the production cost. The response evaluation of fly-ash was carried out in this work, in order to explore its influence on the hardness and microstructural properties of Aluminum composite. In this research, aluminum alloy was reinforced with different amounts (10, 20, 30 and 40 wt. %) of fly ash. The alloy, reinforced with fly ash were fabricated by a stir casting method. Afterwords, the Aluminum composites were characterized based on the hardness and microstructural analysis (phase analysis). The results showed that the hardness gave an optimum property of 74.20N/mm2 at 40wt%. This showed that the addition of fly-ash improved the properties of the composites. This result were further confirmed through the microstructural analysis which showed a good interfacial bonding between the reinforcement (fly-ash) and the matrix (Aluminum). This composite can be applied in automobile and construction industries.