Abstract: Proteostasis is a core biological process through which cells maintain the stability and functional integrity of the proteome via a multi-level quality control network. As a key molecule in the ubiquitination regulatory pathway, the deubiquitinase USP7 can drive tumorigenesis and progression by altering the ubiquitination status of substrate proteins when its expression is aberrant or activity is dysregulated, thus emerging as a critical target in precision cancer therapy. This article systematically outlines the structural features of USP7, its role in regulating substrate protein homeostasis, and its biological functions in tumor development. It focuses on recent advances in USP7-based anti-tumor strategies, including the development of small-molecule inhibitors, applications of proteolysis-targeting chimeras (PROTACs) technology, and exploration of novel approaches such as deubiquitinase-targeting chimeras (DUBTACs). This review provides a systematic theoretical framework and cutting-edge research directions for the development of USP7-targeted anti-tumor drugs.