Sol-gel derived CuO/CuAl 2 O 4 , Co 3 O 4 /CoAl 2 O 4 and Mn 2 O 3 /Al 2 O 3 oxygen carriers were studied in a fluidized bed reactor under CO 2 atmosphere, where the oxygen release characteristics under different temperatures were focused. The mechanism function and kinetics parameters in the oxygen release were obtained from the experimental data. In the process of oxygen release, the phases of CuO and CuAl 2 O 4 performing as active components decompose to Cu 2 O and CuAlO 2 with O 2 generation. While, only Co 3 O 4 and Mn 2 O 3 can release oxygen in Co 3 O 4 /CoAl 2 O 4 and Mn 2 O 3 /Al 2 O 3 oxygen carriers, in which Co 3 O 4 and Mn 2 O 3 are respectively reduced to CoO and Mn 3 O 4 ; and CoAl 2 O 4 and Al 2 O 3 perform as inert carrier. The kinetic analysis shows that the oxygen release of three oxygen carriers can be described by the nucleation and nuclei growth model. This means that after O 2 release the Cu-O bond (as an example) in the oxygen carrier is broken, generates Cu 2 O active sites diffusing away from the reduction centers, and comes together to form Cu 2 O clusters. The mechanism function G(x), the activation energy and the pre-exponential factor have different expressions or different values for different oxygen carriers. The activation energies in the oxygen release of CuO/CuAl 2 O 4 , Co 3 O 4 /CoAl 2 O 4 and Mn 2 O 3 /Al 2 O 3 oxygen carriers, are 226.37, 130.06 and 65.90 kJ/mol respectively; and the pre-exponential factors are 2.99x10 6 s - 1 , 4.96x10 3 s - 1 and 27.37 s - 1 respectively.