The defensin CADEF1 has been known to be up-transcripted in the pepper Capsicum annuum L., upon bacterial attack, abiotic elicitors and environmental stresses. However, the native form of CADEF1 has not been purified from the pepper, and its activity against fungi has been uncertain. In this study, the full-length cDNA of CADEF1 was obtained by fragment piecing-together method. Thereafter, its mature peptide coding sequence was inserted into bacterial expression vector pET28a(+), and the recombinant vector was transformed into Escherichia coli BL21 (DE3). Based on SDS–PAGE and Western blotting analysis, the recombinant CADEF1 was produced as a 5.6 kDa protein in the form of inclusion body in E. coli BL21 (DE3) and the expression level accounted for 15% of the bacterial total protein. Further processing through protein refolding and purification, converted the inclusion body type of CADEF1 into active form with the yield about 13 μg/ml of culture. The refolded CADEF1 significantly showed the activity against growth of the fungal pathogen Verticillium dahliae on average by 67.9% in vitro assay. These results verified the novel activity of CADEF1, which might benefit in prevention of the fungus-related disease in agricultural production.