Carbon leakage has become the core issue of emission trading systems. Using data from Hubei Province, this paper identifies the drawbacks of the prevailing methods for preventing carbon leakage and proposes a new methodology to overcome them, namely, Emission Control Coefficients. In contrast to the common tiered structure method, we found that Emission Control Coefficients generate a dynamic and continuous emission control coefficient for each industry which will improve the effectiveness and fairness of allowance allocation, set aside sufficient time for the low carbon transformation of industries, and balance the needs to protect competitiveness and decarbonize and are particularly suitable for the emission trading systems of developing counties. This paper makes three main academic contributions: Firstly, this paper proposes a new indicator, the abatement potential. Secondly, this paper better distinguishes industrial differences. Thirdly, this paper can better respond to the problem of excess allowances due to technological advances and trade pattern changes.