Abstract: The liability sharing of carbon emission reduction is the foundation to formulate the carbon emission reduction policy and also the important process to perfect the carbon trading market system. In order to define the liability of regional carbon emission reduction in a reasonable manager, the IFCAM was constructed by beginning with the regional difference of carbon emission in land use and giving considerations to the principles of fairness and efficiency. The liability of carbon emission reduction in each county and district was divided under the carbon emission reduction targets of Wuhan Urban Agglomeration in 2020. And it was conducted the feasibility test, hoping to provide reference for liability sharing of carbon emission reduction in Wuhan Urban Agglomeration and relevant areas. The findings showed that:（1）The proportion of carbon emission of urban land use in Wuhan megalopolis exceeds 70%, showing the core-peripheral diminishing distribution. Each region had the obvious difference;（2）Even if 3D apportion model improved fairness of carbon emission in the megalopolis, the overall carbon emission efficiency was only 0.54, which was reduced by 30.77% comparing with 2015, thus it should be further improved;（3）The entire efficiency maintained by the IFCAM was 1, which gave considerations to 3E equity principle on the basis of no decay, thus areas with the higher economic development would reduce the pressure of carbon emission reduction, while areas with the lower economic development would increase the pressure of carbon emission reduction;（4）The inspection findings indicated that based on the IFCAM, the decrease amplitude of carbon emission intensity in each county and city of Wuhan Urban Agglomeration in 2020 could reach the standard. The decrease amplitude of average carbon emission intensity was 19.27%, which exceeding the target(18.78%) distributed by the Hubei Provincial Government. Moreover, the variable coefficient of apportion results was smaller and average carbon emission efficiency was enhanced. The distribution of fairness and efficiency could be solved effectively, showing the feasibility and scientificity.