Assessing the impact of the COVID-19 pandemic on China's carbon emissions is crucial for China to lead global climate change mitigation. However, thorough quantitative analyses of the pandemic's effects on energy use and emissions are still lacking. This is largely because well-known published datasets of greenhouse gas emissions are based on annual statistics that commonly become available one or more years after they are gathered. A high temporal resolution emission dataset is critical to capture the immediate effects of an event such as the COVID-19 pandemic. Such an improved resolution might also allow policy makers to more quickly observe the effects of policies aimed at decreasing CO2 emissions, facilitating rapid adjustments. Here, based on a newly developed, near real-time global emission dataset, Carbon Monitor, we estimate China's daily energy consumption and associated CO2 emissions and use this dataset to estimate the impact of COVID-19 on CO2 emission trends. Such a near-real-time CO2 emission database based on activity data quantifies both anthropogenic CO2 emissions from fossil fuel combustion and cement production. We show that the higher-resolution emission dataset can be used to assess the impact of COVID-19 (and similar future disruptions) within a reasonable range of uncertainty. This study finds that China's CO2 emissions in the first four months of 2020 decreased by 6.9% compared to the same period in 2019, with a total emission reduction of 234.5 million tons of CO2. The provinces of Jiangsu, Hubei, and Zhejiang were most severely affected by COVID-19, accounting for 19.4%, 17.0% and 12.5% of the total reduction in CO2 emissions, respectively. The reduction of CO2 emissions from Shandong, Hebei, Anhui, Henan and Chongqing provinces is more than 10 Mt CO2, and the sum of the reduction from these five provinces accounts for 28.8% of the national total reductions. CO2 emissions in Yunnan Province, Gansu Province, Guangxi Zhuang Autonomous Region, Ningxia Hui Autonomous Region, Shaanxi Province and Xinjiang Uygur Autonomous Region increased slightly compared to the same period in 2019. In addition, COVID-19 has a little effect on CO2 emissions from Qinghai Province and Tibet Autonomous Region. This decrease in atmospheric pollutants is the largest decrease recorded and is consistent with the decrease in air pollutants observed by ground observation stations. This study finds that China's national economy has recovered rapidly. In April 2020, China's carbon emissions returned to the same level observed last year. This study predicts that China's full-year CO2 in 2020 will be 2% lower than in 2019. This will be the first time China has experienced a decline since 1997. China's carbon emissions have not rebound significantly, and the dynamic changes in China's CO2 indicate a rapid recovery of the Chinese economy. Regarding long-term trends, it is still unclear how much China's CO2 emissions will change at the end of this year and how fast the economy and industry will return to normal. With policy support, the economy will be stimulated as the pandemic fades. The IMF predicts that the global annual economic output will decrease sharply by -3.0% in 2020, which is worse than the financial crisis in 2008, based on the assumption that COVID-19 will fade globally in the second half of this year. Based on current emission dynamics, China's emission decline is estimated to be less than 5%, and the future trend will be affected by whether there will be another pandemic in the future. Current statistics are still not capable of comprehensively capturing the dynamics of CO2 emissions during the COVID-19 pandemic, and further monitoring, observation and data collection are urgently needed. © 2021, Science Press. All right reserved.