For studying on pathogenicity mechanism of Fusarium moniliforme,REMI was used to transform protoplasts of FT1 strain with the vector pUCATPH,which contained hygromycin B-resistant gene.More than 300 transformants had been obtained,most of them were quite stable after five rounds of successive culture.25 mutants of morphology and 2 weak pathogenicity mutants were gained by REMI.PCR amplification showed that the hygromycin B-resistant gene had integrated into genomes of the two pathogenicity mutants.The optimum conditions of preparing protoplasts were: the mycelia growing in PDB medium for 14 h,lywallzyme was used to digest the mycelia at 100 r/min,30℃ for 4 h,and 0.7 mol/L NaCl was used as the osmotic stabilizer.