Although nanozymes have been widely developed, directly utilizing light to drive catalytic reactions like natural photoenzymes still remains challenging. Here, we propose that photonanozymes (PNZs), as a novel kind of nanozyme, exclusively possess enzyme-mimicking activity under illumination. Only in the presence of visible light, the as-synthesized TiO2 proposed in this contribution shows excellent specificity of peroxidase-like without any oxidase- or catalase-like activity. The driving force of the light-empowered peroxidase-like photonanozymatic activity is explicated in terms of the photogenerated hot charge carriers in TiO2 PNZs and the accompanied reactive oxygen species. The co-substrates for photonanozymatic reaction over TiO2 PNZs facilitate the formation of the precarious and reactive peroxo-oxygen bridge between TiO2 and H2O2, enabling the catalytic specificity. With the TiO2 PNZ-based biosensing platform for visual glucose detection exemplifying the concept of the application of PNZs, this work may evoke more inspirations to explore strategies for enlarging the scope of photoenzyme mimics.