Calcination-induced catalytic activity of CO oxidation reaction (CO + 1/2O(2) -> CO2) for an intermetallic, AuZr3 and a hydride, AuZr3Hx (x = 4.8) has been studied. The catalytic activities for both samples were originated from the formation of nano-gold particles and nano-crystalline ZrO2, result by oxidation upon calcination. Oxidation of the AuZr3Hx occurred at lower temperature than the AuZr3, gave rise to the formation of more homogenous distribution and smaller sizes of nano-gold particles (similar to 5 nm) on ZrO2, which were responsible for relatively high catalytic performance. This study provides the possibility of hydrogen absorption treatment being a beneficial process for obtaining nano-composite from intermetallic compounds for catalysts.