The objectives of this research was to determine the chemical composition of roscoe extract from methanol and evaluation of antibacterial activity. The phytochemical compound screened by GC-MS method. Forty eight bioactive phytochemical compounds were identified in the methanolic extract of Zingiber officinale. The identification of phytochemical compounds is based on the peak area, retention time molecular weight, molecular formula, MS Fragment-ions and pharmacological actions. GC-MS analysis of Zingiber officinale revealed the existence of the Octanal, 2-Naphthale namine,1,2,4a,5,6,7,8,8a-octahydro-4a-methyl, 1-(Cyclopropyl-nitro-methyl)-cyclopentanol, Endo-Borneol, Decanal, 1,2-15,16-Diepoxyhexadecane, Propanal,2-methyl-3-phenyl, Benzeneacetic acid ,4-(1H-1,2,3,4-tetrazol-1-yl), Ascaridole epoxide, 2-Methoxy-4-vinylphenol, 6-epi-shyobunol, Phenol,2-methoxy-5-(1-propenyl)-,E, Alfa.-Copaene, 8-Isopropenyl-1,5-dimethyl-cyclodeca-1,5-diene, Bicyclo[3.1.0]hexane-6-methanol,2-hydroxy-1,4,4-trimethyl, 7-epi-cis-sesquisabinene hydrate, Alloaromadendrene, Benzene,1-(1,5-dimethyl-4-hexenyl)-4-methyl, 1,3-Cyclohexadiene ,5-(1,5-dimethyl-4-hexenyl)-2methyl-,[S-(R?,S?)], Aromadendrene oxide, 1,6,10-Dodecatrien-3-ol,3,7,11-trimethyl-,(E), 4-((1H)-3-Hydroxy-1-propenyl)-2-methoxyphenol, Butan-2-one,4-(3-hydroxy-2-methoxyphenyl), Longipinocarveol,trans, Cholestan-3-ol,2-methylene-,(3?,5?)-, Bicyclo[4.4.0] dec-2-ene-4-ol,2-methyl-9-(prop-1-en-3-ol-2-yl)-, Corymbolone, Estra-1,3,5(10)-trien-17?-ol, 1-Heptatriacotanol, Fenretinide, Folic acid, Spiro[4.5]decan-7-one,1,8-dimethyl-8,9-epoxy-4-isopropyl-, 7H-6,9a-Methano-4H-cyclopenta[9,10] cyclopropa[5,6]cyclodeca[1, Gingerol, 1b,4a-Epoxy-2H-cyclopenta[3,4]cyclopropa [8,9]cycloundec[1,2-b]o, Cyclopropa[5,6]-A-nor-5?-androstane-3,7-dione,3?,6?-dihydro-17?-h, Olean-12-ene-3,15,16,21,22,28-hexol,(3?,15?,16?,21?,22?)-, Benz[e]azulen-3(3aH)-one,4,6a,7,8,9,10,10a,10b-octahydro-3a,8,1, Naphthalene, decahydro-1-pentadecyl-, 13-Docosenamide,(Z)-, 9,10-Secocholesta-5,7,10(19)-triene-3,24,25-triol, (3?,5Z,7E)-, n-(2,4-Dinitrophenyl)-N?-13-(2,6,6-trimethyl-cyclohex-1-enyl)propylider, n-(2,4-Dinitrophenyl)-N?-13-(2,6,6-trimethyl-cyclohex-1-enyl)propylider, Ingol 12-acetate, 2,2,4-Trimethyl-3-(3,8,12,16-tetramethyl-heptadeca-3,7,11,15-tetrae, Piperine, 2-Methylcortisol, 9-Desoxo-9-x-acetoxy-3,8,12,-tri-O-acetylingol and Propanoic acid ,2-(3-acetoxy-4,4,14-trimethylandrost-8-en-17-yl. Methanolic extract of bioactive compounds of Zingiber officinale was assayed for in vitro antibacterial activity against Proteus mirabilis,Escherichia coli, Pseudomonas aerogenosa, Proteus mirabilis, Staphylococcus aureus and Klebsiella pneumonia by using the diffusion method in agar. The zone of inhibition were compared with different standard antibiotics. The diameters of inhibition zones ranged from 4.93±0.290 to 0.89±0.210 mm for all treatments.