Natural gas combustion characteristics of oxygen carrier particles were investigated in a batch type bubbling fluidized bed reactor (0.05 m ID, 0.6 m high). Three particles, NiO/bentonite, NiO/NiAl2O4, and CoxO/CoAl2O4, were used as oxygen carrier particles. Natural gas and air were used as reactants for reduction and oxidation, respectively. All three oxygen carrier particles showed high gas conversion, high CO2 selectivity, and low CO concentration during reduction and no NOx (NO, NO2, N2O) emissions during oxidation. Moreover, all three particles showed good regeneration ability during successive reduction-oxidation cyclic tests up to the 10th cycle. The gas conversion, CO2 selectivity and CO concentration were maintained to 97% of initial values for all three particles. These results indicate that inherent CO2 separation, NOx-free combustion, and long-term operation without reactivity decay of oxygen carrier particles are possible in the natural gas fueled chemical-looping combustion system with NiO/beotonite, NiO/NiAl2O4 and CoxOy/CoAl2O4 particles.