Small molecule drug candidates with attractive toxicity profiles that modulate target proteins through non-covalent interactions are usually favored by scientists and pharmaceutical industry. In the past decades, many non-covalent binding agents have been developed for different diseases. However, an increasing attention has been paid to covalent binding agents in pharmaceutical fields during recent years. Many covalent binding agents entered clinical trials and exerted significant advantages for diseases such as infection, cancers, gastrointestinal disorders, central nervous system or cardiovascular diseases. It has been recognized that covalent binding ligands can be attractive drug candidates. But, there is lack of resource to support covalent ligand discovery.