<p>Nanozymes, enzyme-like nanomaterials (NMs), present a compelling alternative to natural enzymes due to their superior catalytic activity, stability, and low cost. Among them, cerium dioxide (CeO₂) NMs exhibit diverse catalytic activities, including oxidase, peroxidase, catalase, superoxide dismutase, phosphatase, haloperoxidase, urease, uricase, DNase I, DNA photolyase, and ROS scavenging. The catalytic efficiency of CeO₂ nanozymes is largely influenced by oxygen vacancies, surface valence states, and the Ce⁴⁺/Ce³⁺ redox cycle, which are crucial in enhancing their enzymatic functions. This review explores the different dimensional structures of CeO₂ nanozymes, such as zero dimensions (0D), one dimension (1D), two dimensions (2D), and three dimensions (3D). It outlines their synthesis methods, which include physical, chemical, and biological approaches. Additionally, it examines surface modification strategies like ion exchange, small molecule binding, and macromolecular capping, which can either promote or inhibit their catalytic activity. By providing a comprehensive overview of the development, synthesis methods, dimensional variations, and surface modifications of CeO₂ nanozymes, this review highlights their enzyme-mimicking properties and their application potential in biosensing technologies. Furthermore, it offers insights into future prospects, focusing on advancing their catalytic efficiency and expanding their use across different fields. The review emphasizes the need for continued research to enhance the practical applications of CeO₂ nanozymes, which hold significant promise for the future of biosensing and other catalytic processes.</p>