Abstract：In order to clarify the effect of nitrogen and sulfur interaction on allicin and quality of garlic seedling，a main garlic cultivar ‘G025’ of Shaanxi was used as test material，and a 2 factors 3 level random block test was designed．This experiment sprayed the leaf surface with different nitrogen and sulfur concentrations during the 4-5 leaf stages，and harvested and analyzed the quality of garlic seedlings after 10 days and 20 days，respectively．The results showed that nitrogen and sulfur factors and their interaction had significant effects on the growth of garlic seedlings，and contents of allicin，alliin，sulfur etc. nutritional qualities．20 days after treatment the allicin and alliin contents of garlic seedlings were higher than that of 10 days after treatment．20 days after treatment，the combination of low nitrogen（450 mg · L-1）and medium sulfur（300 mg · L-1）could significantly increase the contents of allicin in leaves and pseudostems．The combinations of high nitrogen（850 mg · L-1）and low sulfur（100 mg · L-1），or low nitrogen（450 mg · L-1）and low sulfur（100 mg · L-1）could significantly improve the content of alliin．
