Abstract: A simple method is reported for hypochlorite determination based on fluorescence 3-aminophenylboronic acid–functionalized molybdenum disulfide quantum dots (B-MoS2 QDs). B-MoS2 QDs with strong fluorescence at 380 nm have been successfully synthesized by the amidation reaction between APBA and hydrothermal MoS2 QDs. Hypochlorite sensing was proposed utilizing the fluorescent quenching effect of 3,3ʹ,5,5ʹ-tetramethylbenzidine dihydrochloride (TMB) on B-MoS2 QDs and the fast redox reaction between hypochlorite and TMB. The fluorescent quenching effect of TMB to B-MoS2 QDs was proved to be caused by static dynamic quenching and inner filter effect. A good linear relationship was obtained in the hypochlorite concentration range from 1 to 20 μM, and the limit of detection (LOD) was 36.8 nM. The proposed fluorescent detection assay was simple and fast, taking only 5 min at room temperature. Satisfactory results were obtained in the standard spike recovery tests on tap water and milk samples, which indicate high potential in constructing fluorescent bio-detection assays.