In this study, 10 pathogenic strains were isolated from the diseased roots of Actinidia arguta by tissue separation. After identification by morphology and molecular biology, the pathogen was identified as Sclerotinia nivalis. The biological properties and drug susceptibility of Sclerotinia nivalis were studied. Results demonstrated that the optimal growth temperature of mycelium was 20 ℃, PSA was the medium for optimal mycelial growth, the best carbon and nitrogen source for suitable mycelial growth were glucose and peptone, respectively; The suitable pH was 8. Full light conditions favor mycelial growth, and the mycelial growth rate was used to test the susceptibility of the pathogen to 8 fungicides. The results showed that the pathogenic bacteria had high susceptibility to 25% prochloraz EC, 50% procymidone WP, 25 g/L fludioxonil SC, 50% iprodione SC, 45% dimethachlon net WP, as EC50＜1.0 mg/L. The biological and drug susceptibility determination of Sclerotinia nivalis was established for the first time, which laid a foundation for the prevention and treatment of Actinidia arguta in the field.