Climate change assessment is central for low-carbon management practice. This paper investigates China’s National Climate Change Assessment Reports of 2007, 2011, and 2015. These three reports are compared with other climate change assessment reports by data mining. The necessity of national climate change assessment is analyzed with the requirements at home and abroad. The latest progress surrounding climate change impacts, adaptation, and mitigation is outlined with the increasing temperature rise in China and the urgency of climate change commitments. The achievements in climate change assessment indicate the increasing climate change vulnerability on sectors and regions in China and the strategies and priorities for low-carbon actions. Distinct gaps and differences are identified in the coverage of industry, regions, and vulnerability assessment between our assessments and other evaluation reports. These gaps and differences demonstrate the importance and future improvements of China’s national climate change assessment in international climate governance. The outlook for China’s fourth assessment report is proposed.