Glucose sensing and monitoring are crucial for biological and medical applications. Compared to existing methods, real-time detection and long-term monitoring are still required. Single-walled carbon nanotubes (SWCNTs) have excellent optical properties for sensing applications, which provide the possibility for designing a new generation of glucose sensors. In this study, we describe a method for covalently conjugate glucose oxidase (GOx) on SWCNTs as an optical glucose sensor. The functional groups are introduced by a photocatalytic reaction which acts as the handle for protein loading on SWCNTs. In this sp3 defect reaction, the optical properties of SWCNTs can be maintained. With a convenient bioconjugation reaction, the GOx could be covalently linked with SWCNTs. Compared to the non-covalent immobilization conjugates, the covalent conjugate sensor exhibits a much stronger optical response toward glucose, and the stability of the biosensor also increases in harsh conditions. At the same time, we also report the changing ratio of the original E11 and defected E11* peak during the bioconjugation reaction, which is also inspiring for reaction monitoring on SWCNTs.