Based on their different mechanisms and involved materials, nanotechnology-based tumor hypoxia-regulating approaches can be classified into the following categories: delivering O2 by natural or artificial oxygen-carrying materials, the hydrolysis of exogenous peroxide, catalytic decomposition of intracellular H2O2 by utilizing catalase or catalase-like nanozymes, and generating O2 by water-splitting photocatalysts. Here, CAT is linked to neoplasm.