Abstract: Cayenne pepper bacterial wilt, caused by Ralstonia solanacearum, is one of the most important diseases in China. Biocontrol is considered to be the most environment safe and efficacious approaches to control the disease. In this study, screening for potential biocontrol agents against the disease was performed based on abilities to inhibit the pathogen in vitro and to colonize host roots in planta. 6 bacterial strains (Corynebacterium sp.BT6, Bacillus spp.FH17, BB11, Escherichiasp.BT4, Serratia sp.J2, and Pseudomonas sp.J3) were selected. All strains exhibited pathogen inhibiting zone diameters larger than 1cm on artificial media and root colonizing population counts higher than 1×10⁵cfu/g root 30d after root-dipping and planting. The disease-controlling efficacy of these strains was assayed both in the greenhouse and in field plots. In greenhouse experiments, the roots of seedlings were dipped in cell suspensions before planting in soils containing R.solanacearum. The disease incidence 40d after treatment was reduced by 42% to 92%, and the yield 71d after treatment was increased by 21% to 110%. Field plot experiments were completed under natural condition without inoculation of the pathogen in Qixia of Nanjing, and Huaiyin of Jiangsu, on cultivars Daguozaofeng and Sujiao 2, respectively. On average, the disease incidence 40d after treatment was reduced by 37% to 73%, and the yield at ripeness was increased by 19% to 79%. All strains tested except the BT6 showed high disease-controlling efficacy and yield increasing potential.