Abstract: CO₂ capture from the flue gas of coal-fired power plants is an important part of China’s goal of carbon pegging and carbon neutrality, and the key lies in the development of highly efficient CO₂ adsorbents. However, water vapor and other impurities are inevitably present in the coal flue gas, which affects the structure of the adsorbent and the CO₂ adsorption mechanism. Therefore, clarifying the influence of water vapor on the structure of adsorbents and the CO₂ adsorption mechanism is the key to developing efficient and stable adsorbents. The effect of water vapor on the structure and CO₂ adsorption mechanism of typical solid adsorbents （including solid amine, activated carbon, metal-organic framework, zeolite, MgO and CaO-based adsorbents） is discussed in detail. For hydrophilic adsorbents such as activated carbon and zeolite, CO₂ adsorption is competed with by water vapor; For the adsorbents with regular pore structure such as metal-organic framework, the structure is destroyed and caused to collapse by water vapor. For solid amine adsorbents, the dehydration reaction is inhibited and the amine efficiency is changed by water vapor. For MgO and CaO-based adsorbents, the specific surface area, pore structure and CO₂ molecular diffusion efficiency are affected by the presence of water vapor. Methods to optimize the structure of adsorbent include hydration reactivation, water vapor pretreatment, adjusting pore size and surface hydrophobic modification, etc. Among them, the hydration reactivation method is associated with large energy consumption and reduces the crush strength of the adsorbent. Therefore, the pore size adjustment method is considered to have limitations for adsorbents with developed and adjustable voids, while the surface hydrophobic modification method complicates the synthesis process, resulting in increased production costs.. In the future, it is necessary to further explore the method of optimizing the modification of the adsorbent based on the influence of water vapor, achieve the reduction of energy consumption through process optimization, and enhance the crushing strength of the adsorbent by adding reinforcement materials and regulating hydration conditions.