In this paper, we observed changes of inulin content and DP from 10 days before Jerusalem artichoke blossomed and 80 days after blossomed. The variation tendencies are almost the same, which increase rapidly at the beginning and then decrease gradually at a lower speed. The maximum of inulin content could reach 12.21% and the maximum of inulin DP could reach 19. Both data reach peak at the similar time which is 40 or 50 days after blossom. It indicates that these changes are related to the growth status of Jerusalem artichoke tubers. Experimental data supplied us with deeper knowledge of inulin content and DP changes in whole growth process of Jerusalem artichoke tubers. Meanwhile, the effects of the inulin on probiotics in the yogurt have also been evaluated systematically. The result shows that inulin with lower DP has better activities, which could be a theoretical basis for further high-value utilization of inulin. These findings mentioned above may be instructive to get inulin with different properties from Jerusalem artichoke in Northeastern China. Further study will be carried out in the near future.