Sucrose synthase, a key enzyme to sucrose metabolism, plays an important role in plant growth and development. We constructed RNAi- SUS3 vector and transferred it into Arabidopsis using Agrobacterium tumefacien mediated vacuum infiltration for analyzing the function of SUS3 . We investigated each AtSUSs expression pattern in transcriptional level and compared phenotype in both wild and transgenic plants. We stained lignin of siliques via Wiesner reaction and observed endocarp cells by using transmission electron microscopy. The results show that AtSUS3 transcriptional expression is suppressed in transgenic plants with no significant phenotypes changing under normal growth condition. However, in transgenic siliques, the expression of AtSUS1 , AtSUS2 and AtSUS4 increase for compensation AtSUS3 silence. As a result, the secondary wall of endocarp cells in transgenic siliques is thickened and the lignification degree is also enhanced. Compared with wild types, the siliques matured earlier and the valves are thinked in transgenic plants during fruit development and maturity. We conclude that AtSUS3 silence may promote siliques maturation.