Global long-term Satellite-based leaf area index (LAI) products have been generated and applied widely for understanding the feedbacks between climate and terrestrial vegetation. However, these long-term LAI products are not internally consistent over time and also not consistent with each other, which means they might be not suitable for serving as reference datasets in long-term global change research. Therefore, there is a strong need for a qualityassured long-term LAI product with reliable, traceable and understandable quality information. The Quality Assurance for Essential Climate Variables (QA4ECV) project is developing a quality assurance framework to provide understandable and traceable quality information for ECVs such as LAI. The LAI produced from this framework will add greater transparency and openness between ECV producers and end users, and facilitate the application of a long-term LAI product for global change research.