Attribution studies include climate change attribution,impact attribution and identification of weather sensitivity.IPCC Sixth Assessment Report Working Group Ⅱ (AR6 WGⅡ) follows the definition of climate change impact attribution in the Fifth Assessment Report Working Group Ⅱ (AR5 WGⅡ),and considers that climate change impact attribution assesses the contribution of climate system changes to observed natural,human or managed system changes.IPCC AR6 WGⅡ sets up a “no-climate change baseline” in the impact attribution studies,and summarizes most recent achievements on the impact attribution of climate change on terrestrial ecosystems,marine ecosystems,coastal systems,water systems,food systems and human society.Compared with the AR5 WGⅡ,the AR6 WGⅡ more specifically describes the impact of climate change on nature,human or managed systems,improves the reliability of some assessment conclusions,and gives more evidence on the social impact of climate change.Although some progresses have been made in climate change impact attribution,the AR6 WGⅡ points out that more high-quality data,more effective methods for quantifying climate change impacts and more comprehensive understanding on the mechanisms of systematic change are still needed to deepen the research on climate change impact attribution.