Abstract: To study the allelopathy of potato extracts from different varieties and different plant parts on following crop millet, and screen out the previous crop potato varieties which are proper for the growth of millet, the potato extracts of different concentrations were prepared by using the ground part and the underground part of seven potato varieties respectively, and the seeds of millet were treated with the extract for the germination experiment. The results showed that all the extracts were significantly inhibited the germination rate, germination potential and germination index of millet. The inhibitory effect was enhanced with the increase of the extract concentration. The root length and vigor index of millet treated with every leaching solution were less than those of the control. The root length and vigor index showed a deceasing trend. The low concentration treatment promoted millet seedling height and fresh weight, while the high concentration treatment inhibited them. The allelopathy effects of different potato varieties on millet were different. In conclusion, the potato has allelopathy on the following crop millet, and‘Xingjia 2’,‘Feuray it’,‘Zhongshu No.5’have the least allelopathy on millet.