Abstract: This paper was aimed to investigate the incentive mechanism of triterpenoid synthesis by antioxidant response in the cultured Cyclocarya paliurus cells under the elicitation of Aspergillus niger elicitor(ANE),and the activity changes of the relative antioxidant enzymes and the expression of related genes were investigated to explain the induction mechanism of ANE from oxidative stress level.Results showed that,the triterpenoid synthesis began to rise in the 10th h after inoculation and reached the peak in the 60th hour. The maximum triterpenoid content was 36.46 mg/g,which was 3.36 times as much as that of control. Meanwhile,the activity of SOD,POD,CAT,PAL,and PLC increased significantly,and several peaks of enzyme activity emerged successively in the cells under ANE stimulation. Moreover,the results of transcriptome detection showed that there were a number of up-regulated related genes including 3 SOD,20 POD,1 CAT,3 PAL,and 3 PLC,among which 3 POD,1 CAT,and 3 PAL were significantly up-regulated(p<0.05). Besides,the transcript abundance of related genes encoding triterpenoid synthetase increased as well. Consequently,it could be deduced that antioxidant response occurred in C. paliurus cells under ANE elicitation,which resulted in the increasing of expression and enzyme activity of genes related to oxidative stress and further improved the triterpenoid synthesis in the cells. The current paper investigated the incentive mechanism of triterpenoid synthesis by antioxidant response in the cultured Cyclocarya paliurus cells under the ANE elicitation,which provided reference for production of secondary metabolites by plant cell culture.