Abstract:[Background] The saline-alkali land as a reserve arable resource is crucial to grain security. Plant growth-promoting rhizobacteria (PGPR) have been proved effective in improving saline-alkali land. [Objective] To explore the methods efficient in isolating PGPR and promote the development and utilization of PGPR in saline-alkali land. [Methods] The rhizosphere soil of soybean plants grown in the heavy saline-alkali land of Dongying City was collected for the isolation of bacteria by the dilution culture method. The effects of pH, organic nutrient level, and NaCl concentration on the isolation were evaluated. The strains capable of solubilizing inorganic phosphorus and producing siderophores were screened on functional plates. The purified isolates were identified by sequencing the 16S rRNA gene. [Results] A total of 443 isolates were successfully sequenced for the 16S rRNA gene, and they were identified as 96 species of 48 genera and 7 potential new species. Among these species, 28 and 13 were capable of solubilizing inorganic phosphorus and producing siderophores, respectively, and 7 species showed both functions. From points of bacterial richness and CFU count, NaCl concentration showed the greatest effect, followed by organic nutrient level, and then pH. Under the oligotrophic condition, NaCl at a concentration ≥3% significantly inhibited the growth of bacteria isolated from saline-alkali soil, which could be alleviated considerably by increasing the organic nutrient level. Considering the CFU count, species richness, new germplasm resources, inorganic phosphorus solubilizing, and siderophore production, a medium containing 1.0% NaCl, 1/50×R2A, and with pH 8.5 was proposed to isolate bacteria from saline-alkali soil. [Conclusion] We isolate a batch of bacterial resources from heavy saline-alkali land and provide methodological reference for isolating new bacterial resources from saline-alkali land in other areas.