To explore the effects of human umbilical cord mesenchymal stem cells(HUMSCSs) on the learning ability and memory of mice SAMP8 with Alzheimer’s disease. Methods： We cultivated human umbilical cord mesenchymal stem cells， provided three doses HUMSCs (2.5×105/0.2 mL/20 g， 5×105/0.2 mL/20 g， 1×106/0.2 mL/20 g) for the transplantation of seven months SAMP8 Alzheimer’s mice by the tail vein， and set up the normal saline group and normal control group R1 mice for comparison. After 45 days， MORRIS water maze and jumping apparatus were used to test the ability of learning and memory of the subjects. Results： Compared with normal control mice R1， normal saline group of SAMP8 Alzheimer’s mice performed significantly worse on the learning and memory tests. But there was significant improvement in Morris water maze test compared with the normal saline group， including shorter escape latency (P<0.05) more platform crossing frequencies (P<0.05)， and in jumping apparatus including less jumping stand error number (P<0.05) and longer step down latency (P<0.05). Conclusion： Low dose of HUMSCs can enhance learning and memory ability of SAMP8 Alzheimer’s mice.