Traditional drug delivery methods are prone to large fluctuations in drug concentration and require multiple frequent doses. As a green material with excellent properties, cellulose has been widely used as a drug carrier for the development and preparation of drug controlled-release system. Based on the mechanisms of slow drug release, such as dissolution-diffusion release, degradation release, and nanochannel-controlled release, the preparation methods of cellulose-based drug carriers are introduced in this paper. The applications of cellulose-based drug carriers in the fields of antitumor therapy, antibacterial therapy, chronic disease treatment, and viral disease treatment are summarized with the aim of providing a useful reference for research on cellulose-based drug carriers.