To observe the effect of photic stimulation on long term potentiation (LTP) and A beta in the hippocampus of 3xTg Alzheimer's model mice. Methods: Twenty 4～6 month 3xTg AD mice were randomly divided into photic stimulation (PS) group and unstimulated (NS) group. Ten wild type mice in the same background were in the control group. AD mice in the PS group received 2 Hz photic stimulation for 4 weeks. After the mice were decapitated, the in vitro hippocampal LTP was induced and the A beta protein content in the hippocampus of mice was detected. Results: The LTP of mice in NS group was significantly inhibited, and the content of A beta in the hippocampus was significantly higher than that in control group (both P<0.05). The level of A beta protein in hippocampus of mice in PS group was significantly lower than that in NS group, while LTP increased significantly (both P<0.05). Conclusion: Photic stimulation enhanced the hippocampal LTP and reduced the content of A beta in 3xTg AD mice model