Abstract: The combustion and mercury migration patterns in "CuO+coal", "SiO₂+coal" and "coal" experiments were studied. Results show that after the reaction between the oxygen carrier and coal in the chemical looping combustion reduction reactor, the main gas component is CO₂, with a small amount of volatile substances such as CO, CH₄ and H₂, etc. Mercury is mainly released in the form of elemental mercury（Hg~0） in the reduction reactor. In the "CuO+coal" experiment, released amount of Hg~0 accounted for 22.6% of the total mercury released amount, which is much lower than the reference group. CuO promotes the migration of mercury to the oxygen carrier during the combustion process, forming particulate mercury（Hg^P）. The O_α on the surface of CuO oxygen carrier is conducive to the conversion and adsorption of mercury onto the surface of the oxygen carriers, resulting in the formation of adsorbed HgO. When CuO is partially reduced, more adsorption sites are exposed, which is conducive to the oxidation of Hg~0.