Abstract: The peroxidase isozyme of twenty-eight accessions of cultivated and wild buckwheat belonging to eight species of genus Fagopyrum including seven species of the big-achene group and one species of the small-achene group were studied by means of po-lyacrylamide gel eletrophoresis(PAGE).The results showed that there are a total of twenty-three bands of peroxidase isozyme,and the variation of band number from four to nine among different buckwheat species.F.esculentum and F.tataricum have a total of six bands and nine bands,respectively.The results about the zymograph and the clustering showed that there are much great difference of zymographs between the big-achene group and the small-achene group and that F.megaspartanium and F.pilus are close to F.esculentum and F.tataricum,respectively,supporting Chen’s hypothesis that F.megaspartanium and F.pilus may be the ancestor species of F.esculentum and F.tataricum,respectively.