In order to understand and regulate the triterpinoid metabolism， the full length sequence of Cyclocarya paliurus squalene synthetase（CpSS） gene was cloned， and the characters and protein structure of this gene were further studied， as well as its’ expression level in the suspended cultured Cyclocarya paliurus cells induced by Aspergillus niger elicitor. Taking Cyclocarya paliurus cell RNA as template， the full length CpSS sequence of 1 667 bp was cloned using RT-PCR and RACE technologies， which contained a complete ORF with 1 245 bp encoding 414 amino acids. The sequence similarities between Cyclocarya paliurus and walnut， grapes， soybeans， licorice， cocoa were more than 85%， especially walnut with the highest similarity up to 97%. Sequence analysis showed that the protein encoded by CpSS was an unstable hydrophilic protein， which had a typical conserved region and domain of squalene synthase and located in the endoplasmic reticulum. There is a cavity in CpSS protein molecular formed by several α-helixes， which was similar to the majority of plant squalene synthase protein. The determination results of real-time fluorescence semi-quantitative RT-PCR indicated that the expression of CpSS gene increased significantly in suspended cultured Cyclocarya paliurus cells induced by Aspergillus niger elicitor， and the expression peaked at the 60 h after inducement. Our study provides a reference for further investigations on the triterpenoid metabolism of Cyclocarya paliurus and the inducement mechanism of fungal elicitor.