Quantitative detection of heparin is of great significance to ensure the safe use of heparin in the clinic. In this paper, a self-assembled fluorescent sensor for rapid detection of heparin was fabricated throughSelectrostatic complexation of chitosan quaternary ammonium salt with 4-(1,2,2-triphenylethenyl) benzoic acid (TPE-COOH), which has aggregation-induced emission (AIE). After the complex encountered heparin, chitosan quaternary ammonium salt preferentially combined to heparin with high negative charge density, and then released the AIE luminogens, resulting in a decrease in the fluorescence intensity of the complex. Therefore, the quantitative detection of heparin was achieved. The results showed that the detection limit of this method was 0.0393 mg/L, and the detection range was 0-14 mg/L. The obtained fluorescent sensor not only had the characteristics of simple preparation, sensitive response, and high selectivity but also had the degradability and biocompatibility of natural polymers.