In this study, leaves of sweet and non-sweet taste Cyclocarya paliurus leaves planted in Wugang, Hunan Province were selected for comparative study to illustrate the mechanism of sweet taste formation. The cDNA libraries were constructed and sequenced. The transcriptome date was analyzed with there terpenoid metabolome and the metabolism pathway. The molecular differences in the formation of sweetness traits of Cyclocarya paliurus were explored. Some 13 key enzyme genes involved in triterpene biosynthesis to have significantly different expression patterns between the two materials by GO and KEGG analysis. Combined with terpene metabolism detection, the accumulation of four kinds of sweet triterpenes in sweet Cyclocarya paliurus leaves was significantly higher than that in non-sweet leaves, indicating that the differential expression of these genes maybe causing different accumulation of sweet triterpenoids in leaves, it’s key to the formation of sweetness traits in Cyclocarya paliurus.