Two isozymes of malate dehydrogenase (MDH) and peroxidase (POD) were performed by PAGE,and their activities were measured to study the formatting mechanism of heterosis of foxtail millet using hybrid millet ‘Zhang No.3,5,6’ and their parents,respectively.The results indicated that:(1)There were 5 bands of MDH isozyme which belong to homotype and tendfemale type in leaf of hybrid millet Zhang and their parents,and 14 bands of POD isozyme which belong to homotype.(2)The isozyme patterns of MDH between hybrid millet Zhang were same as that of their female parent,and that of POD was same as their parents.The tested individuals and parents differed in number,Rf,activity or width of the POD bands,the zymogram was complicated,but it was simple in MDH.(3)The MDA activities of all varieties were the highest in heading stage and there was heterosis of MDH activity in hybrid millet Zhang from seedling to heading stage,and the POD activity was the highest in early grainfilling stage and there was heterosis from heading to early grainfilling stage too,showing a correlation exists between the isozyme patterns both MDH and POD with the formation of heterosis in hybrid millet Zhang.