[Objective] To investigate the diversity of bacteria and fungi in the pathosphere ofPlasmopara viticola and screen out the strains with potential biocontrol effects on grape downy mildew. [Methods] The leaves infected byP.viticola were collected from seven representative grape-producing regions in northern and southern China in two consecutive years. The collected leaves were cultured in a humid environment, and the newly growing downy mildew was aseptically picked by forceps to prepare the sporangial suspensions ofP.viticola. The strains were isolated by the conventional culture method and identified based on the morphological characteristics, BOX-PCR fingerprints, and molecular sequences. Furthermore, the clustering analysis of different strains was conducted. Sporangial inhibition was tested with equal volumes of strain suspension or fermentation mixed with the sporangial suspension ofP.viticola, and the control effects of isolates and their sterile fermentation against grape downy mildew were tested on detached grape leaves. [Results] A total of 90 bacterial strains and 110 fungal strains were isolated, belonging to eight bacterial genera and 14 fungal genera, respectively. The pathosphere ofP.viticola in the same province and the same year exhibited similar microbial community composition. Notably, strains ofPseudomonas spp. andCladosporium spp. exhibited stable populations on grape cultivars collected from different provinces. A majority (over 80.0%) of strains with stable populations in two consecutive years demonstrated significant biocontrol effects against grape downy mildew. SixAcremonium strains with ubiquitous distribution demonstrated the biocontrol effect up to 100.0%. Sterile fermentation of the fungal strainsAspergillus niger NX2F,Thecaphora amaranthi BJ1G, andRhizopus stolonifer BM1L showed the control effects of 100.0% against grape downy mildew. [Conclusion] The culturable bacterial and fungal communities in the pathosphere ofP.viticola were mainly affected by geographical factors in different provinces, and most of the culturable microorganisms presented stable and strong biocontrol effects on grape downy mildew. To the best of our knowledge, it is the first comprehensive report thatAcremonium spp. were epibiotic fungi and consistently associated withP.viticola, providing rich and valuable biocontrol resources for grape downy mildew.