In order to research antimicrobial activity and preliminary structural-activity relationship of chemical constituents of Zingiber officinale,six gingeroloids were isolated and from Zingiber officinale with chromatographic methods.Structure elucidation of the six compounds was based on spectroscopic methods,and they were identified as 5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-4-decen-3-one (1),5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-4-dodecen-3-one (2),5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-4-tetradecane-3-one (3),［6］-gingerol (4),［8］-gingerol (5),and ［10］-gingerol (6),respectively.Antibacterial activities of the six compounds against 15 Gram-positive and Gram-negative bacteria were performed with antimicrobial paper diffusion method.As a result,compounds 1 and 4 showed the best antibacterial activity against the tested strains,while 6 showed no antibacterial activity against all tested strains.The bioassays revealed that antibacterial activity of the enol-type compounds (1,2 and 3) against Gram-positive bacteria was better than that of the gingerol-type compounds (4,5 and 6),whilst the antibacterial activity of gingerol-type compounds against Gram-negative bacteria was better than that of enol-type compounds.Furthermore,increase of the fat chain length of gingeroloids may lead to the decrease of antibacterial activity.