Objective To explore the effect of acupuncture on the dendritic structure of the hippocampal CA1 area and cognitive functions in Alzheimer’ s disease mice. Methods Twenty-four male rapidly aging SAMP8 mice were randomly divided into model and acupuncture groups with 12 mice each. Another 12 male normal aging SAMR1 mice were used as the control ( control group). Mice in control and model groups were untreated. Mice in the acupuncture group received acupuncture treatment for 8 weeks ( once every other day). The acupuncture sites were Baihui, Shenshu, and Taixi. A Morris water maze test was sued to assess mouse cognitive functions. After collecting the mouse hippocampal CA1 area, Golgi staining was used to observe the structure of pyramidal cell dendrites. Immunohistochemical staining was used to detect expression of Aβ_1-40 and Tau. Western blot was used to measure BDNF, SYN, and MAP2 protein expression levels. Results (1) Compared with the control group, the model group had a higher escape latency on the 5^th day of water maze training, while the number of cross-platforms was lower (P<0. 05). Compared with the model group, the acupuncture group had a lower escape latency on the 5^th day of water maze training, and a higher number of cross-platforms (P<0. 05). (2) Compared with the control group, the lengths of basal and apical dendrites, and the numbers of basal dendrites and branches of apical dendrites were all lower in the model group (P< 0. 05). Compared with the model group, the above indicators were all higher in the acupuncture group (P<0. 05). (3) Compared with the control group, the average optical density of Aβ_1-40 and Tau expression was higher in the model group (P<0. 05). Compared with the model group, the above indicators were lower in the acupuncture group ( P<0. 05). (4) Compared with the control group, the protein expression levels of BDNF, SYN, and MAP2 were lower in the model group (P<0. 05). Compared with the model group, the above indexes were higher in the acupuncture group (P<0. 05). Conclusions Acupuncture at Baihui, Shenshu and Taixi might improve the cognitive function of rapidly aging SAMP8 mice by activating BDNF/ SYN/ MAP2 signaling pathway and improving the length and number of dendritic branches in the CA1 region of hippocampus.