Abstract: In order to compare the feeding value of Helianthus tuberosus L. silage and whole plant corn silage, the effect of adding lactic acid bacteria （LAB） and cellulose （CE） on fermentation quality of Helianthus tuberosus L. silage was assessed, and the optimal packing density of Helianthus tuberosus L. for storage was determined. Three separate experiments were designed and carried out in this study. Experiment 1： The silage was prepared by using Heliaathus tuberosus L. and whole plant corn which were cut at early blooming period and 1/3 milk line period, respectively. Three duplicate samples for both silages were prepared. Experiment 2： Helianthus tuberosus L. was ensi]ed with LAB （2.0 g/t fresh weight）, CE （2.0 g/t fresh weight） and LAB （2.0 g/t fresh weigh） ＋ CE （2.0 g/t fresh weight）, and the silages without additives were served as control （CK）. There were 3 duplications for each treatment. Experiment 3： Helianthus tuberosus L. was packed at densities of 550, 600, 650, 700, 750 kg/m^3 respectively and was ensiled in laboratory silos. There were 3 duplications for each packing density. The results showed that there were no differences in fermentation quality between Helianthus tuberosus L. silage and whole plant corn silage. The contents of neutral detergent fiber （NDF） and acid detergent fiber （ADF） were significantly lower in Helianthus tuberosusL, silage compared to whole plant corn silage, and the in vitro dry matter digestibility （IVDMD） in Helianthus tuberosus L. silage was significantly higher than that in whole plant corn silage （P〈0.05）, which indicated that the feeding value ofHelianthus tuberosus L. silage is better than whole plant corn silage. Adding LAB significantly decreased the pH value and ammonia nitrogen/total nitrogen （AN/TN）in Helianthus tuberosus L. silage and significantly increased the content of lactic acid （LA,P〈0.05）, which indicated that adding LAB improved the fermentation quality of Helianthus tuberosus L. silage. No significant differences in fermentation quality between the silages with and without CE were observed （P〉0.05）. As the increase of packing density, the pH value and ammonia nitrogen/total nitrogen （AN/TN） in Helianthus tuberosus L. silage was found to be significantly decreased （P〈0.05）, and the content of LA was significantly increased （P〈0.05）.When the packing densities were no less than 650 kg/m^3, no butyrie acid was detected and the AN/TN was below 10%, which indicated that the optimal packing density for preparation of Helianthus tuberosus L. silage with superior fermentation quality was 650 kg/m^3.