Abstract: In this study，the expression vector of green fluorescent protein was transferred into the strain NQ8GⅡ4 by PEG-mediated protoplast transformation. Transformants of no difference with the wild strain were obtained by biological assay and PCR analysis. The cell walls of young hypha of NQ8GⅡ4 strain was lyzed with enzymes to generate protoplasts，which were used to insert the exogenous DNA randomly under PEG8000 mediated transformation. Fifty-seven transformants of NQ8GⅡ4 that showed hygromycin B resistance and fluorescence signal were obtained. The transformation frequency of NQ8GⅡ4 was 2 850 transformants per mg DNA. The transformants were compared with wild type strain for mitotic stability，phenotype，fluorescence，antagonistic activity and pathogenicity and a transformant with similar properties to wild-type strain was screened out. The results have established foundation for futher study on the endogenesis and biocontrol mechanism of strain NQ8GⅡ4.

Key words: Lycium barbarum, GFP, endophytic fungus, Fusarium netamophilum, protoplast, transformation efficiency, stability