Because of China’s global responsibilities to address climate change, the country has made a commitment to limiting the growth of future emissions using policy measures, such as funding mitigation research and regulating energy efficiency requirements directly. Extensions of these policies, such as the measures to improve energy efficiency, use of carbon taxes, and changes to the mix of electricity generation in the country, are also of interest to China. This article applied a computable general equilibrium (CGE) model to examine the effects of such energy efficiency and climate change policy options in the post-COVID-19 era in the China economy. The study findings show that even modest measures can have significant effects on emissions with marginal economic impacts, given the current level of development in the China electricity generation and transportation sectors. It is estimated that a 5 RMB per ton carbon tax will reduce emissions by 4.1% and GDP by 0.27%. Emissions drop by 8.2% and GDP drops by 0.54% when energy efficiency increases by 2% across the China economy, respectively. As a final result, a 5% shift away from burning coal would reduce emissions by 9.0%, while GDP would increase by 1.3%. It has been shown that even low carbon taxes can encourage a notable cleaner energy system.