The catalytic partial oxidation of methane to synthesis gas over Ni/gamma -Al2O3 catalyst has been investigated in a fluidized-bed reactor. The results showed that an isothermal operation and the performance near to thermodynamic equilibrium could be obtained in a fluidized-bed reactor. A study on carbon deposit showed that there was a low rate of carbon formation in a fluidized-bed reactor. The CH4 conversion as well as CO and H-2 selectivities remained constant at similar to 92, similar to 94 and similar to 99.0%, respectively, during 100h running. Neither phase transformation of the support nor remarkable Ni loss was found on the catalyst after 100h running.