Objective To determine the effect of fibroblast growth factor 2 (FGF2) injection on the behavior and astrocytes activation in the hippocampus in the rats of posttraumatic stress disorders (PTSD). Methods Single prolonged stress (SPS) was used to establish the PTSD rat model. Then a single high dose of FGF2 (50μg/kg) was given by intraperitoneal injection in 7d after the model establishment. Another 7d later, open-field test (OF) and elevated plus maze (EPM) test were used to evaluate rats’ spontaneous activity, anxiety and depression behaviors. Immunofluorescence staining and double immunofluorescence Western blotting were used to detect the expression of glial fibrillary acidic protein (GFAP) in the hippocampus in normal, PTSD, and FGF2 treated rats for astrocytes activation and expression level respectively. Results FGF2 treatment resulted in significantly decreased anxiety and depression behaviors compared with the PTSD rats, and enhanced the expression of GFAP obviously in the hippocampus. Conclusion FGF2 obviously attenuates anxiety and depression behaviors in the rats after SPS, which might be due to its enhancement in astrocyte activity in the hippocampus.