Abstract: The experiment used two potato varieties‘Dongnong 308’and‘Yanshu 4’as tested materials, and aimed to research the absorption and accumulation of starch in tubers of different potato varieties, and to study the four key enzymes related to its synthesis and provide a reasonable basis for potato improvement. After the top of the potato stolonic began to expand, the key enzymes of starch synthesis, the dynamic accumulation of starch and the amylose dynamic accumulation in leaf blade and tubers were measured. The results showed that, the four key enzymes in different periods of starch accumulation and synthesis process showed different activity strength, which in turn controlled the beginning and the rate of the starch biosynthesis, and then influenced the synthesis and accumulation of potato amylose and amylopectin. And both the starch content and starch content of each component of‘Dongnong 308’were more than that of‘Yanshu 4’in every period. The reason was that the key enzymes of starch synthesis of‘Dongnong 308’were higher than that of‘Yanshu 4’ .