The invention relates to a bacterial strain for preventing and treating soil-borne fungal diseases of peanuts in continuous cropping and a fungicide of the bacterial strain, wherein the bacterial strain is Pseudomonas protegens, and is assigned with the accession number of CGMCC No.11539. The 16s rRNA base sequence of the bacterial strain is shown as SEQ ID No:1. The bacterial strain has high activity in generating chitinase (degrading cell walls of pathogenic bacteria hyphae), and has the obvious degrading capacity for various soil-borne fungous pathogenic bacteria mycelia, such as fusarium, rhizoctonia and verticillium chlamydosporium. For the fungicide provided by the invention, the seed dressing use amount is only 20-30 kg/mu normally, the fungicide can be used for effectively preventing and treating the soil-borne fungous diseases, such as root rot, damping off and southern blight frequently occurring in peanuts continuously planted in dry fields, the control effect achieves 55% or above, in addition, the bacterial strain has the advantages of small use amount, wide antimicrobial spectrum, obvious yield-increasing effect and the like, so that the influence of the soil-borne diseases on the yield loss of the peanuts in continuous cropping is effectively alleviated.