[Background] Myxobacteria are a group of higher prokaryotes with social behavior. They have great research value in screening natural drugs because their metabolites have rich, diverse and novel biological activities. [Objective] We studied the diversity of myxobacteria in Daxing’an Mountains of Inner Mongolia, and isolated and purified the culturable myxobacteria, and studied their antimicrobial activities and screened strains against Phytophthora infestans. [Methods] The diversity of myxobacteria was studied by PCR-denaturing gradient gel electrophoresis (DGGE). Culturable myxobacteria were isolated from 15 soil samples collected from Daxing’an Mountains by rabbit dung pellets inducing method, Escherichia coli inducing method, and filter paper inducing method. The purified strains were identified by morphological observation, physiological and biochemical characteristics, and the 16S rRNA gene sequence analysis. Then, the antimicrobial activities of the strains were determined by plate confrontation method. [Results] The results of DGGE showed that 13 genera of myxobacteria were identified from 15 soil samples, covering most of the known genera of myxobacteria and some of the unclassified myxobacteria. 88 strains were isolated in this study and 22 of them were purified. The purified strains belonged to two genera, Myxococcus and Corallococcus, and 8 species, Myxococcus xanthus, Myxococcus flavescens, Myxococcus virescens, Myxococcus coralloides, Myxococcus stipitatus, Corallococcus macrosporus, Corallococcus exiguous, Corallococcus coralloides. All of the purified myxobacterial strains exhibited one or more kinds of antimicrobial activities. 19 strains had the activity against E. coli. 14 strains had the activity against Phytophthora infestans. Eight strains showed the activity against Staphylococcus aureus. 13 strains had the activity against Saccharomyces cerevisiae. Seven strains showed the activity against Bacillus subtilis. [Conclusion] Myxobacterial resource in Daxing’an Mountains of Inner Mongolia is rich. Myxococcus and Corallococcus could be the dominant populations of myxobacterial community in this region. The purified myxobacterial strains exhibited one or more kinds of antimicrobial activities and 64% of them have the activity against Phytophthora infestans, which has the potential value for further research in the future.