Abstract: In order to reveal the mechanism of fertility promoting the tuber development，the potato landrace Cardinal（Solanum tuberosum L.）was sampled as material，and the changes of polyamines（PAs），gibberellin（GA3）and jasmines（JAs） in the process of the tuber development under different fertility levels were analyzed by HPLC. The result of the experiment follows：（1）The contents of three kinds of PAs（Put，Spm，and Spd）had two peak values at primary and middle stage in the tuber development respectively comforting with the trend of decrease-increase-decrease. But the contents had different respondents to different fertility levels. In middle stage of tuberization PAs contents under moderate fertility level were higher than that under low and high fertility levels. High fertility made the Put content decrease，the peak time of Put advance，and the peak time of Spm and Spd postpone. With the increase of fertility the peak value of Put/Spd reduced continuously and the peak time advanced.（2）In the middle stage GA3 was the highest under low fertility level and lowest under moderate fertility level. Under low fertility level JAs content was low in all stage. And in the middle stage the JAs content under moderate level was higher than that under low and high fertility levels. The GA3/JAs under low and high fertility levels increased firstly and then decreased. The change trend is reverse to that under the moderate fertility level.（3）JAs content had significant positive correlation with the content of Put，and significant negative correlation with the contents of Spd and Spm. The reasonable fertility level could improve the contents of PAs and JAs，reduce the content of GA3 in the middle stage of tuberization and favor the tuber development of potato.