Abstract: 45 single colonies with certain morphological characteristics were isolated from saline-alkali soil in northern Ningxia, and the 16S rRNA sequence of the strains were sequenced and identified by genome extraction technology. Results showed that there were 16 strains of actinomycetes, including 13 strains of Streptomyces, 3 strains of Acidophilum. The experimental results of antibacterial activity exhibited that all 16 strains of actinomycetes had antibacterial activity, among which 12 strains of secondary metabolites had significant antibacterial activity againstProteus vulgaris, 12 strains of secondary metabolites had obvious inhibitory activity againstStaphylococcus aureus, and 9 strains of secondary metabolites had certain growth inhibitory activity againstCandida albicans. The researches demonstrated that the microbial strains isolated from saline-alkali soil in northern Ningxia had strong antibacterial or bacteriostatic activity. This study not only enriched the microbial resources in special habitats, but also laid a foundation for further isolation of antibacterial lead compounds.

Key words: saline-alkali soil, microorganisms, actinobacteria；secondary metabolites, antibacterial activity