SBPbox (Squamosa promoter Binding Protein box) genes, belonging to plantspecific transcription factors, involved in many important processes of plant growth, including leaf development, embryogenesis, plastochron formation, vegetative and reproductive phase transitions, et al. SbSBP17 was amplified by RTPCR using total RNA extracted from BTx623 inflorescences, phylogenetic analysis and semiquantitative PCR were performed. This study establishes the foundation for further research of SbSBP17 functions. SbSBP17, consist of 2 introns and 3 exons, encoded a protein of 444 amino acids carrying a typical SBP domain(195-269 aa). According to phylogenetic tree analysis, eighteen SBP17 proteins were clustered into three groups (Ⅰ-Ⅲ). Ⅰ and Ⅱ group contained only monocotyledonous proteins, while dicotyledonous protein only existed in group Ⅲ. The orthologous proteins of SbSBP17 was PWZ17260.1 in maize. By analyzing the promoter sequence, several ciselements were detected, including MSAlike, CATbox and RYelement, et al. Expression analysis indicated SbSBP17 was inflorescencespecific gene. With the growth and development of sorghum inflorescence (length increase), the expression level of SbSBP17 gradually increased and arrived the peak value (40 times than the lowest level) in the 10 cm inflorescence, and then declined significantly by 50% above in 20 cm inflorescence. It was presumed that the expression of SbSBP17 possibly decreased gradually and ultimately disappeared.