In the field of tumor imaging and therapy, the aggregation-caused quenching (ACQ) effect of fluorescent dyes at high concentration is a great challenge. In this regard, the aggregation-induced emission luminogens (AIEgens) show great potential, since AIEgens effectively overcome the ACQ effect and have better fluorescence quantum yield, photobleaching resistance, and photosensitivity. Polyethylene glycol (PEG)-polymer is the most commonly used carrier to prepare nanoparticles (NPs). The advantage of PEGylation is that it can greatly prolong the metabolic half-life and reduce immunogenicity and toxicity. Considering that the hydrophobicity of most AIEgens hinders their application in organisms, the use of PEG-polymer encapsulation is an effective strategy to overcome this obstacle. Importantly, bioactive functional groups can be modified on PEG-polymers to enhance the biological effect of NPs. The combination of powerful AIEgens and PEG-polymers provides a new strategy for tumor imaging and therapy, which is promising for clinical application.