Porphyrins and their associated derivatives have been widely used as photosensitizers for photodynamic therapy (PDT) of tumors. To overcome the limitations of porphyrin photosensitizers in PDT, the marriage of porphyrins and nanotechnology offers a new perspective to improve the efficacy and safety of porphyrin-based PDT. To date, various organic and inorganic nanoparticles have been developed for porphyrin delivery for high payload photosensitizers, protection from premature release of photosensitizers, and tumor-selective targeting. In this article, we summarize the strategies for porphyrin photosensitizer delivery, including encapsulation, covalent conjugation, self-assembly for PDT, and characterization methods of singlet oxygen (1O2) generation. We focus on the summarized strategies of improving cancer PDT efficacy by nanotechnology. Finally, the challenges and outlook for porphyrin-based nanocomposites-mediated PDT are discussed.