Abstract: Eight benzene homologues in seawater were determined by head-space GC. The temperature and time chosen for equilibration of the sample in the head-space vessel were 40 ℃ and 30 min respectively. Nukol capillary chromatographic column (30 m×0.25 mm, 0.25 μm) was used for the separation, and hydrogen FID was adopted in the determination. Under the optimum conditions, the 8 benzene homologues were separated within 13 min. Linear relationships between values of peak area and mass concentration of the 8 benzene homologues were obtained in the same range of 10.0-200 μg·L-1, with same detection limit (3S/N) of 2 μg·L-1. Using seawater sample as matrix, tests for recovery were made by standard addition method; values of recovery found were in the range of 93%-119% with RSD′s (n=6) in the range of 1.1%-5.3%.