This study was to investigate the effects of combined application of actinomycetes Act12 bio-control agents and potassium humate on growth and microbial flora in rooting zone of Salvia miltiorrhiza Bge.Taking conventional transplantation treatment as control, we used root dipping with actinomycetes Act12 bio-control agents and potassium humate to evaluate survival rate, biomass and resistance to root-knot nematode of S. miltiorrhiza; The abundances of soil bacteria (B), fungi (F) and actionmycetes (A) were determined using the dilution plating technique. Predominant microorganisms were identified using 16S rRNA and ITS sequence analysis. Results were used to evaluate the microecological changes in soil microflora of S. miltiorrhiza root zones with combined application of actinomycetes Act12 bio-control agents and potassium humate.The results showed that: 1)Under Act12 combined with potassium humate treatment (T20), emergence rate increased by 8.7% compared with the control treatment, and mortality rate decreased by 39.0%; Stem-leaf natural weight, root natural weight, root natural weight per plant, root dry weight and root dry weight per plant were 6.1%、28.6%、11.1%、36.3% and 9.0% higher than the control, respectively. 2)Combined application of Act12 agents and potassium humate can adjust soil microecological balance, modify microflora and microbial community composition. In rhizoplane soil, compared with the control treatment, A/F increased by 95.0% under Act12 combined with potassium humate treatment. In S. miltiorrhiza roots, under Act12 combined with potassium humate treatment, the number of bacteria was 195.0% higher than the control. While fungi and actinomyctes were not detected. 3)In rhizosphere and rhizoplane soil with Act12 and potassium humate, 6 predominant microorganisms might be beneficial, which included 3 bacteria isolates namely A. nitroguajacolicus, R. radiobacter and P. frederiksbergensis, 3 actinomycetes isolates namely S. diastatochromogenes, S. lateritius and S. cavourensis; 2 predominant microorganisms were suspected harmful isolates, included 1 bacteria isolate B. frigoritolerans and 1 actinomycetes isolate S. turgidiscabies. 4)Combined application of Act12 agents and potassium humate may control the disease of root-knot nematode. The disease incidence of root-knot nematode in S. miltiorrhiza decreased by 49.3% under using Act12 agents combined with potassium humate.These results suggested that the combined application of Act12 bio-control agents and potassium humate not only promoted S. miltiorrhiza growth and yield, but also enhanced plant disease resistance and adjusted soil microecological balance in rooting zone.