Photodynamic therapy (PDT) has emerged as a promising strategy with higher selectivity and spatiotemporal control than conventional therapies. However, deep hypoxia in tumours has hampered the clinical use of PDT. In this study, a novel multifunctional cluster nanotheranostic agent (AuPd-BSA CN) was fabricated to generate a high amount of reactive oxygen species, regardless of oxygen dependence under 660 nm laser irradiation. The structure and properties of the AuPd-BSA CN were characterised using various technologies. The synthesised AuPd-BSA CN with high biocompatibility served as a superior photodynamic agent, showing prominent antitumour properties under laser irradiation. Additionally, the glucose oxidase-like activity of the AuPd-BSA CN synergistically enhanced the therapeutic performance. Notably, the intrinsic characteristics of the AuPd-BSA CN include dual-modal second near-infrared window fluorescence/photoacoustic imaging capabilities for monitoring and tracking the in vivo tumour therapeutic process. This work provides innovative insights into the AuPd-BSA CN as an “all-in-one” nanoplatform for cancer therapy.