Chemical looping combustion (CLC) of coal can effectively realize the capture and storage of CO2, which is of great significance for China to achieve the goal of carbon peaking and carbon neutral. Mercury (Hg) pollution during CLC of coal needs to be effectively solved because of its high toxicity to human and corrosion to aluminum CO2 compression equipment. In order to promote the effective treatment on Hg pollution from CLC, the effects and mechanisms of gasification medium, gasification products, oxygen carrier (OC), and reaction temperature on Hg release, conversion and migration during the process of CLC were summarized, and the development suggestions were proposed aiming at the problems. CO2 cannot directly oxidize Hg0 homogeneously, but it can inhibit the promoting effect of HCl on Hg removal by the OC. H2O vapor can not only enhances the release of Hg by promoting the precipitation of volatiles in coal, inhibiting the melting of pore structure, and improving coal combustion efficiency, but also reacts with Hg to generate Hg(OH)2 which is then decomposed into HgO and Hg0, and inhibits the conversion of HCl to Cl thereby inhibiting the oxidation of Hg0 to Hg2+. Strong reductive gasification products such as CO, H2 and NH3 inhibit the oxidation of Hg0 by consuming the surface oxygen of the OC. H2S will react with the surface active oxygen of the OC to form surface active sulfur and then promote the removal of Hg0 by the OC. However, the too much high concentration of H2S will lead to the formation of cyclic sulfur or chains sulfur on the surface of the OC that are not active in the oxidation of Hg0. HCl can enhance the performance of the OC on Hg removal. The promotion effect of HCl at low temperature (80-280 ℃) is attributed to the Eley-Rideal mechanism of HCl pre-adsorption, and the promotion effect at medium temperature (280-580 ℃) is ascribed to the Langmuir-Hinshelwood mechanism, and its promotion effect at high temperature (above 580 ℃) is mainly attributed to the homogeneous oxidation of Hg0 by HCl. The promotion of OC on Hg0 oxidation is mainly attributed to the direct oxidation of Hg0 to HgO by reactive oxygen species in the OC, the oxidation of H2S to reactive S, and the oxidation of HCl to reactive Cl and Cl2. The increase of temperature in fuel reactor enhances the release of Hg from coal, but also promotes Hg0 oxidation by promoting the production of Cl and inhibiting the production of CO. The increase of temperature in air reactor not only benefits to the oxidation of Hg0 in the air reactor, but also inhibits the release of Hg0 from the outlet of the air reactor by enhancing the full combustion of coal and weakening the adsorption of Hg by coke. Considering the influence of H2O vapor content on gasification rate, Hg release and Hg0 oxidation, it is proposed to determine the appropriate H2O vapor content to achieve the synergistic effect on enhancing gasification rate, reducing the release of Hg, and promoting Hg0 oxidation. Aiming at the synergistic effect of OC in achieving efficient oxygen transfer and enhancing Hg0 oxidation in fuel reactors, it is proposed to determine an appropriate OC to realize the "one-body dual-purpose" of OC in oxygen transfer and Hg0 oxidation. In view of the influence of fuel reactor temperature on Hg release and Hg0 oxidation in coal, it is proposed to determine the appropriate fuel reactor temperature to minimize the release of Hg in coal in the fuel reactor and enhance the oxidation of Hg0 thereby promoting the enrichment and purification of CO2. In view of the influence of air reactor temperature on Hg0 oxidation, it is proposed to determine the appropriate fuel reactor temperature to enhance the oxidation of Hg in the air reactor as much as possible, thereby reducing the release of Hg from the outlet of air reactor.