Fly ash has a high potential to be converted into geopolymeric material due to its abundant supplies and low cost. However, large particle size of the fly ash caused low reactivity which results in low properties of the end product. The improvement on the fly ash properties by mechanical activation allows it as a new possible raw material in wider application besides solving the low reactivity issue which hindered its range of utilization. In this study, fly ash was mechanically activated by high energy planetary ball mill for 1 hour at different speed, ranging from 100 to 350 rpm and with varied ball to powder ratio (2:1, 3:1 and 4:1). The effects towards its particle size, specific surface area and morphology were determined by particle size analyzer and SEM. It was observed that, increasing of speed to 350 rpm and 4:1 ball to powder ratio (BPR) results in finest size of fly ash where at d(0.1), d(0.5) and d(0.9) the sizes were 1.861, 6.765 and 17.065μm respectively and largest surface specific area (1.46 m2/g). © 2014 Trans Tech Publications, Switzerland.