 This study proposes a novel platinum nanosyme, point NP, loaded reactive oxygen species, ROAS, responsive prodrug nanoparticle, CPTTKHPPH slash point NP, which can efficiently catalyze the decomposition of hydrogen peroxide, H2O2, into oxygen to relieve hypoxia and enhance photodynamic therapy, PDT. This point NP-based prodrug nanoparticle can also be used as a tumor diagnosis agent with desirable long circulation and enhanced in vivo targeting. In vitro and in vivo experiments show that CPTTKHPPH slash point NP can effectively inhibit tumor proliferation and growth. Therefore, this study provides a promising strategy for chemotherapy and PDT synergism and may lead to a new cancer theranostic agent. This article was authored by Inghao, Yuwen Chen, Xinlong He, and others.