Bead-on-string electrospun fibers containing camptothecin (CPT) are fabricated on the surface of knitted silk fibroin (SF) meshes. Microscopic characterization reveals that the bead-on-string structure is prepared successfully and CPT is mainly located within the beaded structure. Interestingly, the CPT-loaded beaded SF mesh (CPT-SF mesh) has excellent mechanical properties. More importantly, it is able to perform a sustained CPT release without burst release. In vitro cytotoxicity tests further indicate that the CPT-SF mesh shows much stronger anticolon cancer activity in comparison with SF meshes and beaded SF meshes. Hence, the CPT-SF mesh has great potential as a promising local drug delivery system for colon cancer treatment.