In this paper, 4 kinds of organic compounds in water were detected by 7890B Agilent gas chromatog. system. The 4 kinds of organic compounds were: 7 kinds of benzene series compounds BETX including benzene, toluene, ethylbenzene, xylene, m-xylene, o-xylene, styrene, 5 kinds of volatile halogenated hydrocarbons including chloroform, carbon tetrachloride, tribromomethane, trichloroethylene, tetrachloroethylene; 8 organochlorine pesticides including α-BHC and β-BHC, γ-HCH, δ-BHC, p,p'-DDE, p,p'-DDD, o,p'-DDT, o,p'-DDT; 7 kinds of organic phosphorus pesticides including dichlorvos, trichlorfon, demeton, dimethoate, methyl parathion, malathion and parathion. The addition of volatile halohydrocarbons (concentration were chloroform, 400 μg·L-1, carbon tetrachloride, 200 μg·L-1) and benzene series compounds (400 μg·L-1) in water was determined, the target compounds were relative standard deviation (RSD) were less than 2.5%. At the same time, the relative standard deviation RSD range of organic chlorine was 0.97% - 3.7% and the recovery was 89.5%-104.9%. The relative standard deviation of organic phosphorus was 1.45%-2.94% and the recovery was 90.4%-98.8%.