Abstract: Objective To investigate changes and the main influence factors of peripheral hemogram of workers occupationally exposed to benzene. Methods Blood routine test was performed in 672 workers (538 exposed and 134 non-exposed) in a petrochemical enterprise.The exposure level,employment history and other potential affecting factors were investigated.The data were analyzed by linear trend and non-condition Logistic regression method. Results The compliance rate of benzene concentration were 94.3% at work-sites,and that of individual exposure level were 100%.The abnormality of peripheral blood and leucopenia among benzene-exposed workers were 4.65% and 7.25% respectively,and were higher than those of controls (χ²=8.014,4.388,respectively,P<0.05).The female exposed workers had higher rates of aglobulia (7.21%) and hypohemoglobinemia (3.60%) than those of males (1.41% and 0.23%,respectively)(χ²=9.524,7.512,respectively,P<0.05).The exposure time and gender (female) played an important role.The OR values of different peripheral hemogram indicators in female exposed workers varied from 3.108 to 15.925,compared with the male exposed workers. Conclusion Female benzene-exposed workers are vulnerable populations and need more protection.Current occupational exposure limit of benzene in China is not safe for them.