Abstract: [Objective] We investigated the promoter activity of yigP gene and analyzed its transcriptional regulatory sequence.[Methods]We cloned promoter fragment into promoter probe plasmid which has a reporter gene lacZ,thus the promoter activity could be measured by detecting β-galactosidase activity. Then,the promoter region was minimized by cloning different truncated promoter fragments into promoter probe plasmid. Using site-directed mutagenesis technology,we introduced site mutations in some key sequences and investigated their effects on promoter activity.[Results] The promoter region of yigP gene was determined,and also the -10 region and -35 region were identified. Meanwhile,a negative regulatory sequence just upstream of yigP promoter was discovered,and our results show that these sequences have important influence on the transcriptional regulation.[Conclusion] We identified the transcriptional regulatory sequences of yigP gene,and this facilitated our understanding of gene transcription.