To understanding the amylose content and the structure and function of the genes regulating starch synthesis(GBSSI), the amylose and amylopectin content, genotypes of GBSSI and sequencing of 100 broomcorn millet germplasm were conducted in this study. The results showed the proportion of amylose content ranged from 0-22.78%(average 6.07%)and the amylopectin content ranged from 4.55- 56.73%(average15.3%)of all resources. The proportion of waxy millet with amylose less than 3.7% was 36 % , and the completely waxy materials was 24%. The primer M5/R11 could effectively identify the genotypes of S0, S-15 and S0S-15.SThe PCR products from int5Lf/R3 and M12/R12 were digested by ACCⅠand EcoNⅠ and the genotypes of GBSSI were effective identification. Nine genotypes were found in 100 millet germplasm, the most numerous genotype is S₀/Lc (33%), the second is S_-15/L_F (25%) and the least is heterozygous genotypes S₀/S_-15/L_F, S₀/S_-15/L_Cand S₀/S_-15 /L_Y/L_FF (2%, respectively ). The S₀/L_c and S_-15/L_Fwere the main genotypes of WX and wx millet. A large number of new SNPs loci were found in local varieties such as Gangu heichanbei, black millet, Qingyang esiniu and bred varieties such as Jinshu9 and Chimi2 By gene sequence alignment. The SNPs can be used in gene function research and identification of millet varieties. The results of this study have important significance to guide the breeding and quality improvement of millet in the future.