Abstract: The Fischer-Tropsch synthesis (FTS) over a spraydried ironbased catalyst reduced at different conditions was investigated in a continuous stirred tank reactor. The effects of reduction temperature and duration on the FTS performances as well as bulk compositions and other properties of the catalyst were determined. The results indicate that the extent of reduction and carburization was intensified by prolonging the reduction duration or by increasing the reduction temperature. The catalyst activity and stability was enhanced with the reduction at 270℃ compared with those reduced at lower temperature (240℃) or unreduced samples. The working catalyst loss during FTS resulted in the catalyst rapid deactivation at lower reduction temperature. The product distribution shifted towards lower molecular weight hydrocarbons with increasing reduction temperature or prolonging reduction duration at the same temperature.