Abstract: Two sesame breeding lines, KUUS709 and YZH11, were used to study the degradation of sesamin, sesamolin, water content and dry matter during seed germinating process at 21℃. The results showed that sesamin content and sesamolin content continuously decreased with seed germinating process, and showed slow-fast rate and changes occurred at 36 hours and 48 hours separately. Water content and dry matter accumulation continuously increased with seed germinating process, and showed a “S” curve at a slow-fast-slow rate at early, mid and late germinating process and changes occurred at 24 hours and 84 hours for water content, 36 hours and 96 hours for dry matter. There were significant positive correlations between water content and dry matter, sesamin content and sesamolin content in seed germinating process from 1 hour to 108 hours. Water content, dry matter had significant negative correlations with sesamin content, sesamolin content in germinating stages. These results provide a theoretical basis for the role of sesamin content and sesamolin content in the study of physiological mechanism of the germination process.