Abstract: Photodynamic therapy (PDT) is a new modality for cancer therapy, which has been used in the clinical treatment for various tumors, such as skin cancer, bladder cancer and prostate cancer. Most photosensitizers have the disadvantages of hydrophobic, low bioavailability and the limited tumor targeting ability. The nanoscale delivery systems can improve the solubility of photosensitizers and enhance their accumulation at the tumor sites. The multifunctional nano-delivery systems are prepared in combination with other anti-tumor drugs to enhance the anti-tumor effect. In addition to addressing the issues of poor solubility and the insufficient tumor targeting ability, the nanoscale delivery systems need to improve the pharmacokinetic properties of photosensitizers, facilitating their rapid accumulation at the tumor sites and quick elimination in vivo, and reducing the skin phototoxicity. This review summarizes the recent clinical application of PDT of cancer, the development of photosensitizers, the delivery systems for photosensitizers and the combinatorial application with other therapeutic methods. The goal is to present an understanding of knowledge on the design of new types of photosensitizers and its clinical application in PDT of cancer.