The tumor microenvironment features over-expressed hydrogen peroxide (H2O2). Thus, versatile therapeutic strategies based on H2O2 as a reaction substrate to generate hydroxyl radical (•OH) have been used as a prospective therapeutic method to boost anticancer efficiency. However, the limited Fenton catalysts and insufficient endogenous H2O2 content in tumor sites greatly hinder •OH production, failing to achieve the desired therapeutic effect. Therefore, supplying Fenton catalysts and elevating H2O2 levels into cancer cells are effective strategies to improve •OH generation. These therapeutic strategies are systematically discussed in this review. Furthermore, the challenges and future developments of hydroxyl radical-involved cancer therapy are discussed to improve therapeutic efficacy.