This study makes an attempt to demonstrate the feasibility of a technique to embed the catalyst on ammonium perchlorate (AP) surface, in aluminized composite solid propellants. Micron sized iron oxide (IO) and nano sized IO were used in this study and its effect on the viscosity and burn rates of composite solid propellants were recorded. Burn rates of propellants prepared with this catalyst embedded AP were measured using a Crawford bomb and observed to be increasing using this technique due to the proximity of the catalyst with AP. The increase in burn rate obtained with micron sized and nano sized catalyst embedded on AP were 27.4% and 7.3%, respectively over those mechanically mixed in the propellant. The end of mix viscosity of the propellant prepared with nano IO was observed to be highest (4.27 × 103 Poise) when it is mechanically mixed in the propellant. The viscosity of the propellant was observed to improve to 3.79 × 103 Poise with the use of the technique of embedding the nano catalyst on AP as the total number of particles reduced. These explanations were the result of a computational model of randomly packed particles of AP, aluminum and catalyst generated for a propellant with 1% catalyst. © 2017 The Combustion Institute