Objective To observe the impact of ginkgo biloba extract in rats with chronic cerebral ischemia on the expression of PSD-95 protein and the content of amino acid neurotransmitter.Methods A total of 42 SD rats were divided into the sham group (n=12), the model group (n=14) and the ginkgo biloba extract group (n=14) by random number table method. Cerebral ischemia rats were produced by permanent ligation of bilateral common carotid arteries . The rats in the ginkgo biloba group were intrgastric administrated with ginkgo biloba extract suspension 28 mg/kg daily for 40 days, since 2 hours later after the surgery. The rats in the sham and model groups were intragastric administrated with equal-Volume nomal saline daily for 40 days, since 2 hours later after the surgery. The expression of PSD-95 protein was detected by immunohistochemistry techniques with image analysis. The content of Glu and GABA in the thalamus was determinated by OPA-pre-column derivatization and HPLC fluorescence detection method.Results The expression of PSD-95 protein (cortex was 212.58 ± 45.02vs.244.20 ± 34.28, thalamus was 132.33 ± 28.32 vs.272.00 ± 62.14) were significantly lower in the cortex and thalamus of the model group than those of the sham group (P<0.01). The content of GABA (6 081.46 ± 2 388.91 mmol/Lvs.8 280.45 ± 3 388.49 mmol/L) in the thalamus of the model group rats was significantly lower than the sham group (P<0.05). Ginkgo biloba extract could significantly improve the expression of PSD-95 protein (cortex was 237.89 ± 34.41 vs.212.58 ± 45.02, thalamus was 226.18 ± 75.80 vs. 132.33 ± 28.32) in the cortex and thalamus of chronic cerebral ischemia rats (P<0.01), and significantly improve the content of Glu and GABA (Glu was 10 523.78 ± 3 639.72 mmol/L vs.6 081.46 ± 2 388.91 mmol/L, and GABA was 18 440.93 ± 7 476.88 mmol/Lvs.11 239.83 ± 4 411.79 mmol/L) in thalamus with chronic cerebral ischemic rats compared with the model group rats (P<0.01).Conclusion Ginkgo biloba extract could regulate the levels of Glu, GABA and selectly regulate the PSD-95 experssion in the cortex and thalamus of cerebral ischemia rats.