Proponents of distributive justice with regard to energy hold that every household has the right to affordable access to energy. However, when passively participating in clean energy reform policies, households, and especially low-income households, are often forced to use energy beyond the scope of affordability, resulting in distributive injustice. However, research on the quantitative estimation of injustice in energy distribution is still rare. In this paper, an evaluation model of energy vulnerability and distributive justice is established through the “reverse deduction method,” and the change value of energy vulnerability before and after energy reform is used to calculate the loss value of distributive justice, which is used as the basis for energy policy evaluation. Taking the policy of replacing coal with natural gas for rural heating in Gaocheng District, Hebei Province, China as a case study, the value of lost distributive justice is calculated. The results show that 34.51% of households experienced distributive injustice after the energy reform, while 19.34% of households improved their energy vulnerability and achieved energy justice through energy subsidy policies. However, 46.15% of households were able to adapt to the energy reform independently without subsidies, which indicates a waste of resources in the energy subsidy policy. The policy implication of these results is that differentiated energy subsidy policies should be implemented according to household energy vulnerability, so as to maximize the policy benefits on the premise of ensuring justice in household energy distribution and minimizing injustice. The empirical study proves that the method of assessing injustice in energy distribution based on the “reverse deduction method” of energy vulnerability is feasible and a new attempt.