The agronomic traits，dry matter content and yield of two potato cultivars(Chuanyu 117 and Mira)underdifferentnitrogen(N)levels were studied in an aeroponic system. The results showed that plantheight，stemdiameter，leafnumber，leaf area，chlorophyll content，stolon number，dry matter content，tuber number and yield were significantlyaffected by N levels. The cultivars had a significant effect on plant height，stem diameter，leaf number，chlorophyll content，stolonnumber，tubernumber，yield and harvest index. The agronomic traits except chlorophyll content under the N 240 mg/L treatment displayed the highest level of the five treatments. Plants showed sub-normal growth if the N level was too high.As the N levels increased，the dry matter content of leaves，stems，roots and tubers first increased and then decreasedfor twocultivars，and reached to maximum values under the N 240 mg/L treatment. N levels had significant effects on bothtuber number and yield for two cultivars. With the increasing of N levels ranging from 120 mg/L to 600 mg/L，the tuber number and yield per plant increased and then reduced sharply. The tubers and yield per plant reached the peak under theN 240 mg/L treatment，and was significantly higher than those under the N 600 mg/L treatments. The tubers and yield perplant respectively increased by 71.6% and107.8%，91.7% and 83.1% of two cultivars compared with the high Nlevel(600mg/L). The tuber size distribution of 0.5～ 1 g under the N 600 mg/L treatment was significantly higher than the N 240 mg/Ltreatment. Ingeneral，the suitable N level for high yield was 240 mg/L for production under this study.