In view of the carbon reduction pressure faced by provinces and cities under the “ double carbon” target, a forecasting method for peaking carbon emissions was proposed. Using Tapio decoupling index analysis method and the LMDI model, combined with Chongqing’s economic development data and carbon emission data, the influencing factors of carbon emission were analyzed and the peak situation was predicted. The results show that: overall, the carbon emissions in Chongqing had increased in the past 15 years, but the annual carbon emissions only accounted for 1% ~ 2% of the national carbon emissions in the same period; from the perspective of the proportion of carbon emissions in the four major energy industries of coal, oil, gas, and electricity, the proportion of carbon emissions from coal and electricity declined significantly, and the proportion of carbon emission from oil and gas increased significantly; the decoupling of economic growth and carbon dioxide in Chongqing was relatively good, and it has been in a state of relative decoupling of expansion; Chongqing’s carbon emissions are mainly affected by urbanization, population growth and economic growth; according to the forecast results, under the benchmark scenario, Chongqing’s carbon emissions will peak at 206 million tons in 2034, and in the peak scenario mode, in 2029, the peak carbon emissions will peak at 185 million tons, 21 million tons less than the traditional model. This paper puts forward countermeasures and suggestions for the green development of Chongqing, such as optimizing the industrial structure, building a clean, low-carbon, efficient and diversified energy system, and accelerating green industry, green transportation and technological innovation. It has certain reference significance and reference value for all regions to make specific measures to achieve the goal of “double carbon”.