The determination of honey authenticity is of importance to ensure its quality and safety. There is an urgent need of effective methods to detect adulterated honey. A simple, rapid, and effective HPLC-DAD method was developed to detect honey adulteration by rice syrup, using a characteristic compound from rice syrup, which is presently difficult to detect by current analytical methods. The characteristic compound was identified as 2-acetylfuran-3-glucopyranoside (AFGP) by MS and NMR. Based on HPLC analyses, the average concentration of AFGP was 92 ± 60 mg/kg in rice syrup. However, AFGP was not detected in any of the natural honey samples, so it could be used as a marker for the detection of honey adulteration by rice syrup. The developed method enabled a rapid detection of honey samples adulterated with 10% rice syrup. Using the developed method, 16 out of 186 honey samples from some markets were found to be adulterated with rice syrup.