Tumor is one of the major diseases that endanger people’s health. At present, the treatments used for tumor include surgery, chemotherapy, radiotherapy and so on. Nonetheless, the traditional treatments have some disadvantages, such as insufficient treatment effect, liable to cause multidrug resistance, toxicity and side effect. Further research and exploration of tumor treatment schemes are still necessary. As the energy converter of cells, mitochondria are currently considered to be one of the most important targets for the design of new drugs for tumor, cardiovascular and neurological diseases. Nano-drug delivery carriers have the characteristics of being easily modified with active targeting groups, and it can achieve accurate targeted drug delivery to cells and organelles. This paper reviews the application of mitochondrial targeted nanoparticles in tumor diagnosis and treatment from the aspects of inhibiting tumor cell proliferation, promoting tumor cell apoptosis, inhibiting tumor recurrence and metastasis, and inducing cell autophagy.