Abstract: Trehalose-6-phosphate synthase(TPS), which plays an important role in the synthesis of trehalose has received much attention in recent years. Research into TPS has mainly focused on bacteria and fungi. However, little research in plants has been reported. This paper describes the cloning and functional analysis of TPS from Arabidopsis. The Arabidopsis cDNA sequence of TPS in the pET30a(+) vector was heterogeneously overexpressed in BL21 of E. coli. Then, TPS was cloned into the plant expression vector pBI121 and transformed into tobacco. The expression of target gene in the transgenic tobacco plants was confirmed with real-time PCR. The transgenic tobacco line S5 showed higher trehalose level, which enhances the tolerance of transgenic plant to salt stress.