CIPK (CBL-interacting protein kinase) is a serine / threonine protein kinase which plays an important role in response to stress in plants. In this study, MsCIPK8 was obtained by using RT-PCR based on transcriptional analysis of alfalfa in response to saline-alkaline stress. Sequence analysis of MsCIPK8 showed a 1341 bp CDS encoding 446 amino acids with a relative molecular mass of 50.73 kDa and an isoelectric point of 6.72. MsCIPK8 performed an N-terminal kinase domain and a C-terminal NAF/FISL domain as a CIPKS family protein. Bioinformatics analysis indicated that MsCIPK8 is a soluble protein with a high proportion of random coil in secondary structure. Phylogenetic analysis showed that MsCIPK8 was most closely related to MtCIPK8 (Medicago truncatula).Four difference sites were found in the two protein sequence alignment, of which 3 were in the conserved domain. MsCIPK8 had induced high expression in response to low temperature, drought, salt and salt-alkali. The expression of MsCIPK8 in roots and leaves had the highest transcript abundance at 12 h and 3 h under low temperature stress respectively. Under saline stress, the highest expression level of MsCIPK8 in roots was detected at 12 h. Under saline-alkaline stress, the expression of MsCIPK8 in roots and leaves remained high after 12 h. Under drought stress, the expression of MsCIPK8 in roots and leaves reached the highest expression level at 12 h. These results indicated that the expression of MsCIPK8 might be related to the resistance of alfalfa to abiotic stresses such as drought, low temperature, salt and salt-alkali.