Abstract: Benflumetol was reported as a new antimalarial drug by professor Ron-xian Deng et al. The drug was awarded a first prize of National invention in 1990 for it's new structure, high effect for The treatment of pernicious malaria and low side reaction and so on. In this paper MS and LC-ESI-MS were applied to identify The plasma drug and drug's urine excreta of several male health volunteers after The drug oral administration.