Abstract: The integration of organic and inorganic materials has been widely used in various applications to generate novel functional nanomaterials characterized by unique properties. Functional crystalline framework nanosheets and their synergistic effects have been studied recently for possessing the advantages of functional species as well as crystalline framework nanosheets. Hence, we have focused on the preparation methods and applications of functional crystalline framework nanosheets in this review. We introduced crystalline framework nanosheets and discussed the importance of integrating functional species with nanosheets to form functional crystalline framework nanosheets. Then, two aspects of the preparation methods of functional crystalline framework nanosheets were reviewed: in situ synthesis and post-synthesis modification. Subsequently, we discussed the properties of the crystalline framework nanosheets combined with various functional species and summarized their applications in catalysis, sensing, separation, and energy storage. Finally, we have shared our insights on the challenges of functional crystalline framework nanosheets, hoping to contribute to the knowledge base for optimizing the preparation methods, expanding categories, improving stability, and exploring potential applications.