Starting from addressing two types of externality problems, this paper establishes a general equilibrium analysis framework to examine the coordinated realization of carbon reduction and non-fossil energy development goals under the two policies of carbon tax and non-fossil energy subsidy. Additionally, it comprehensively evaluates the impacts of these two policies on economic development and energy structure. The results show that: First, levying differentiated carbon tax rates on various sectors results in a lower unit emission reduction cost compared to levying a uniform carbon tax rate all sectors. Second, the carbon tax mainly exerts a direct inhibitory effect on the output and consumption of traditional fossil energy sectors. This can significantly inhibit the growth of energy-intensive industries, thereby having a significant effect on the optimization of industrial structure. In contrast, non-fossil energy subsidy is more effective in promoting the production and consumption of non-fossil energy sources. Third, both a uniform carbon tax rate and differentiated carbon tax rates on carbon emission sources can achieve the goal of carbon peak by 2030. However, to simultaneously achieve the goals of reducing carbon intensity and increasing the share of non-fossil energy, carbon tax revenues should be further used to subsidize non-fossil energy consumptions. Fourth, a carbon tax is likely to bring losses to GDP, whereas non-fossil energy subsidy can increase GDP. Using carbon tax revenues to further subsidize non-fossil energy consumptions can offset the negative impact of a single carbon tax policy on the economy, and may even generates a significant positive effect. In the future, China should levy differentiated carbon tax rates on carbon sources not covered by the existing carbon market, and allocate the carbon tax revenues to subsidize non-fossil energy consumption. By adopting this combination of constraints and incentives, China can fully leverage the advantages of policy integration to achieve both carbon reduction and non-fossil energy development goals.