Abstract: A desorption electrospray ionization mass spectrometry(DESI-MS) method was developed to determine methylglyoxal(MG) present in beers. This method utilized 1,2-diamino-4,5-dimethoxybenzene to convert MG to 6,7-dimethoxy-2-methylquinoxaline, and then determined the derivative by DESI-MS. 1×10^－5 mol•L^－1 MG in water and 5×10－5 mol•L^－1 MG in Yan Jing beer can be determined using this method. This time-saving method may provide a way for high-throughput analysis of MG in beverages.