Abstract: Adverse environmental factors such as salinity, drought and cold limit the growth and productivity of Medicago sativa, the most economically important forage legume worldwide. In this study, the complete coding sequence of NtCIPK2 was cloned from a halophyte Nitraria tangutorum, ligated into a pMD-19T simple vector and bi-directionally sequenced. The CDS of NtCIPK2 was 1362 bp and was identical with a NtCIPK2 gene in GenBank (accession number KC823044). This fragment was inserted into the plant transformation vector pPZP221 under the control of the cauliflower mosaic virus (CaMV) 35S promoter, and then the recombinant vector pPZP221-NtCIPK2 was transferred to Agrobacterium tumefaciens strain GV3101 by the CaCl₂ freeze-thaw method. Hypocotyls of M. sativa were transformed with GV3101 cells harboring pPZP221-NtCIPK2 by co-cultivation. Seven seedlings were obtained after callus induction and gentamycin selection. Then the seedlings were sampled to detect the gentamycin-resistant gene aacC1 by PCR and target gene NtCIPK2 by reverse transcription-PCR analysis. PCR detection indicated that NtCIPK2 was integrated into the Medicago genome in all seedlings. However, RT-PCR detection suggested that NtCIPK2 was overly expressed at the transcriptional level in three seedlings, and gene silencing might be occurring in some seedlings due to the difference in insertion sites of the exogenous gene. A solid foundation for further study of the performance and genetic stability of transformed plants and advanced breeding of Medicago varieties with strong resistance to abiotic stresses is offered.