Multicolor fluorescent polymeric hydrogels (MFPHs) are three-dimensionally cross-linked hydrophilic polymer networks with tunable emission color. Different from the classic fluorescent materials used primarily in dry solid states or solutions, MFPHs exist as highly water-swollen quasi-solid state and thus present many promising properties of both solid and solution, including tissue-like mechanical properties, intrinsic soft and wet nature, fabulous biocompatibility, along with responsive volume, shape and fluorescence color change. These advantageous properties hold great potential in many frontier applications like sensing, bioimaging, information encoding, encryption, biomimetic actuators, and soft robotics. This review is intended to give an in-depth overview of the recent progress in the field of MFPHs with particular focus on the diverse construction methods and important demonstrated applications. Current challenges and future perspectives on MFPHs are also discussed to attract more research interest and promote the future design of MFPHs with fascinating functions and applications