Afforestation and the growth of planted forest are considered as a key strategy to mitigate global warming and to keep global warming below 2 ℃, as well as an important measurement for ecological restoration and forestry sustainable development, by increasing vegetation coverage and biomass, absorbing and sequestrating carbon dioxide. The "young stand-age effect" of CO₂ absorption by plantation has contributed to global CO₂ absorption by afforestation in the middle and high latitudes exceed that of natural forest. The preservation area of plantation in China ranks the first in the world, accounting for 36% of the national forest land area. In recent decades, China's afforestation has contributed more than 10% to global greening. Afforestation impacts the temperature, precipitation, cloud formation, and wind force, etc. by changing the land surface biogeochemical and biophysical processes. And the impacts were observed variations across different climate zones and different regions, which depends on the balance between the greenhouse gas budget, radiation energy budget and water vapor budget. In this paper, the urgent needs of afforestation activities at home and abroad under the background of climate change, the research progress of climate regulation effect of afforestation and its biogeochemical and biophysical mechanisms are reviewed. Afforestation affects the microclimate in the forest such as light, temperature, humidity and precipitation. It then affects ecological processes such as photosynthetic respiration, vegetation growth, water transpiration and radiation energy balance, thus influences the regional climate system. In addition to affecting the exchange of CO₂, water and energy balance, afforestation also releases Biogenic Volatile Organic Compounds (BVOCs), which affects the short-term climate forcing factors such as aerosols, O₃ and CH₄. Because the physiological, phenological and structural changes of vegetation affect the biophysical processes such as energy, water vapor and momentum exchange between the land surface and the atmosphere, which may enhance, weaken or even offset its carbon sink benefits, plus the additional effects generated by atmospheric chemistry and aerosols, afforestation may also intensify climate change taking into account carbon regulation and biophysical effects. Although the increasing area, the volume per unit area of plantation in China is only 36% of that of natural forest, with poor quality, unreasonable structure, low productivity and weak ecological function. The contents that need to be further explored in the current research were summarized. The future needs of afforestation research should focus on systematic and in-depth study of biogeochemical and biophysical mechanisms, promote sustainable forest management, restore forests with intact structure, and change to the tradeoff of multiple ecological regulation services.