Objective:To construct lentiviral vector carrying activity-defective mTERT (deleting amino acid 702-712,named mTERTΔ) and to detect its expression and function. Methods:Mice mTERTΔ gene was amplified by our previous constructed plasmid pDC315-EGFP-mTERT carrying the whole gene encoding mTERT by deletion mutant PCR. Then,eukaryotic expression vector of GV287-EGFP/mTERTΔ was constructed. After DNA sequence analysis,mTERTΔ was cloned into lentiviral vector pGC-LV to construct recombinant vector pGC-LV/mTERTΔ-EGFP. pGC-LV/mTERTΔ-EGFP was transfected into 293T cells by Lipofectamine 2000 to package lentiviral particle LV-mTERTΔ-EGFP. The particles were transfected into neuronal stem cells and primary neurons. TRAP-PCR was performed to detect telomerase activity,and fluorescence microscopy was performed to observe fragment expression and cell proliferation. Results:TERTΔ gene fragment was successfully constructed,and the analysis of DNA sequence proved that the recombinant lentiviral vector pGC-LV/mTERTΔ-EGFP was successfully constructed. Package of lentiviral particle LV-mTERTΔ-EGFP were transfected into neuronal stem cells and primary neurons. The expressed mTERTΔ detected by telomerase activity test was activity defective,and inhibited neural stem cell proliferation and endogenous mTERT function. Conclusion:The lentiviral vector of LV-mTERTΔ-EGFP was constructed successfully and infected cells could express activity-defective mTERT.