In order to actively respond to global climate change and reduce carbon dioxide emissions,China has proposed to achieve a carbon dioxide emissions peak in 2030. Achieving peak carbon emissions is both an international commitment in China's global climate negotiations and a necessary choice for China to achieve economic restructuring and sustainable development. A carbon emissions peak under policy constraints have a certain degree of impact on China's economic development. Based on the 7- sector CGE model,which includes climate protection expenditure,we simulated the economic impact of China achieving peak carbon emissions in 2025, 2030 and 2035. The results show that the earlier the time of achieving the peak of carbon emissions,the greater the economic impact. Three kinds of carbon emission peak scenarios, government revenue and savings have decreased significantly,while the rest of the economic indicators have not caused much impact. The impact of the peak of carbon emissions on the construction industry is small,while the output of other sectors may increase slightly. On the whole,2030 is the best time for China to achieve a peak in carbon emissions. We suggest that China adopt more climate protection policies to achieve the peak of carbon emissions in China. The country should increase its emphasis on carbon sequestration,protect the absorption capacity of forests to carbon and achieve a win-win situation for carbon reduction and carbon enrichment. Carbon emission peak time of 2030 is the best time for China's carbon emissions peak and to prematurely achieve this target in carbon dioxide emissions will have a negative impact on economic growth and output decline in all sectors.