Abstract Imine‐linked covalent organic framework on amino functionalized silicon substrate was constructed via a step‐wise reaction between 1,3,5‐benzenetricarboxaldehyde and 1,4‐diaminobenzene. The obtained material was used as biosensor for bovine serum albumin (BSA) adsorption and probe DNA immobilization, which extended the application of covalent organic frameworks (COFs) to a new field.