Assessment of Policy Benefit Configurations of Net-Zero Emissions: The Impact of Carbon Trading Policy Synergy on Carbon Neutrality Goals

China’s carbon neutrality plan centers on a carbon trading policy system integrating market economy, guidance, regulation, command-and-control, and fiscal measures into an inter-domain synergy. Based on the system science methodology, by leveraging the gray system evaluation method and the multiple regression model, a carbon neutrality policy analysis system has been formed. This paper constructs a policy synergy model to examine its role in achieving net-zero goals. This article measures the policy synergy and effectiveness of China’s carbon neutrality goals in different years through policy evaluation theory and coupling models. Results show China’s net carbon emissions have passed through three cycles—rapid rise, gradual growth, and slow decline—while policy synergy peaked in 2011, 2014, and 2016, aligning with changes in emission growth rates. The significance of this discovery indicates the pulse effect of China’s green policies. In key starting years such as the 12th and 13th Five-Year Plans, China has invested a significant amount of green policy resources. Synergy levels vary by measure: When applying market economy tools, the deterrent effect of command-and-control should be reduced; command-and-control should be paired only with regulation; fiscal measures should be balanced against guidance to avoid counteracting effects. Internal equilibrium between measures is crucial, with mandatory and flexible tools configured separately to maximize policy effectiveness for net-zero emissions. This study expands the quantitative research on policy coordination and effectiveness analysis. At the same time, it provides policy-level guidance and optimization for the realization of the carbon neutrality goal, avoiding the waste and redundancy of policy resources