Methane production using syngas is a feasible way for overcoming the shortage of natural gas supply and a clean utilization of coal. The full-loop circulating fluidized bed will be a good choice to improve the methane production and extend the catalyst lifetime. This work is the first attempt to adopt the full-loop reactor for producing methane, and also the ready for industrial application. Methanation process is investigated numerically in full-loop fluidized bed over Ni/Al2O3 catalyst. The influences of operation parameter on reactants conversion and CH4 yield are evaluated. Meanwhile, the performance of water gas shift reaction is taken into consideration during reactions to improve the conversion rate. The fluidization behavior and reaction characteristic are analyzed for better understanding the methanation process.