Photodynamic therapy is a safe and noninvasive treatment method based on photosensitizers and light. It has broad application prospects in cancer treatment and sterilization. Photosensitizers react with oxygen under light excitation to produce reactive oxygen species with high reactivity. Excessive reactive oxygen species in cells can oxidize and damage cellular components such as proteins, nucleic acids and lipids, and induce cell apoptosis or necrosis. The emerging photosensitizers with aggregation-induced emission (AIE) characteristics can emit strong fluorescence under light excitation in the aggregate state, and efficiently produce reactive oxygen species at the same time, which solves the problem of fluorescence quenching of traditional photosensitizers in the aggregate state. AIE photosensitizers are easy to realize image-guided photodynamic therapy, which has attracted much attention in recent years. Mitochondria, as cell energy factories, are rich in oxygen and are ideal targets for photodynamic therapy. Mitochondria are more numerous in cancer cells and play an important role in both tumorization and programmed cell death. Currently, the AIE photosensitizers targeting the mitochondria of cancer cells are mainly cationic compounds, including pyridium ions, quinolinium ions, isoquinolinium ions and triphenylphosphenonium ions. This review summarizes the molecular types and design strategies of AIE photosensitizers targeting the mitochondria of cancer cells, as well as their applications in photodynamic therapy of tumors.