Developing simple and accurate QY detection methods is of great significant importance in ensuring food safety including drinks. Manganese dioxide nanoparticles (MnO2 NPs) with different morphologies were synthesized by hydrothermal method. Manganese dioxide/graphene (MnO2/GR) nanocomposites were directly prepared on the surface of glassy carbon electrode (GCE) by electrochemical reduction. The materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The effects of nano-MnO2 with different morphologies on the performance of quinoline yellow (QY) detection was investigated. The experimental findings revealed that MnO2 nanorods (MnO2 NRs) had better properties than both MnO2 nanowires (MnO2 NWs) and MnO2 nanotubes (MnO2 NTs). Under optimal experimental conditions, a good linear relationship between peak current of QY on GR/MnO2 NRs/GCE and concentrations ranging between 0.1 μM˜6.0 μM and 6.0 μM˜60 μM were observed, and 0.04 μM was the detection limit. The fabricated sensor was successfully tested to detect QY in soft drinks.