Ulcerative colitis (UC) is a chronic non‐specific inflammatory disease of the intestines with a high prevalence. Polymer‐prepared nanoparticles are well‐targeted, highly biocompatible, and have high potential for personalized therapy. Polymer nanoparticles are able to achieve localized therapy through their unique design. First, this review compares the advantages and disadvantages of natural and synthetic polymeric materials as well as describes the application of polymeric nanoparticles in UC therapy. Then, the preparation, characterization methods, and current challenges of common polymer nanoparticles are presented. Next, one‐by‐one examples of polymer nanoparticle‐targeted drug delivery strategies for the treatment of UC are presented. In addition, polymer nanoparticle‐based therapeutic approaches for UC, including anti‐inflammatory therapies, reactive oxygen species scavenging therapies, and intestinal flora modulation therapies, are presented. Finally, future research directions for polymer nanoparticles in UC therapy are discussed and current challenges are identified. The aim of this paper is to provide valuable references and guidance for researchers to design and develop novel UC therapies.