Abstract: The effect of reaction modes, i.e.fluidized bed and fixed bed operations, on catalyst life for hydrogen production from methane decomposition was investigated over a 75Ni15Cu10Al catalyst and a 2Co1Al catalyst.Pure methane was used as the feed.The results showed that the apparent reaction rate in the fluidized bed was much higher than that in the fixed bed, indicating that in the fixed bed the reaction was transport-controlled.The carbon formed was characterized with TEM technique, and the results showed that the size of metal particles increased with rising reaction temperature, and at the same reaction temperature the size of metal particles on the catalyst in the fixed bed was larger than that on the catalyst in the fluidized bed, signifying that fluidized bed reactor is beneficial to preventing the sintering of active metals.