Data-Juicer is a comprehensive multimodal data processing system aimed at delivering higher quality, richer, and more digestible data for large language models (LLMs). It offers a systematic and reusable data processing library, supports collaborative development between data and models, allows rapid iteration through a sandbox lab, and provides features like data and model feedback loops, visualization, and multidimensional automated evaluation, helping users better understand and improve their data and models. Data-Juicer is actively maintained and regularly enhanced with more features, data recipes, and datasets.