To observe the expression of brain-derived neurotrophic factor (BDNF) and postsynaptic density-95 (PSD-95) in hippocampal CA1 region of rat with morphine dependence for different times and withdrawn for 1 week, and investigate the influence of that morphine dependence is withdrawn on rat hippocampal CA1 area.Animal models of rats with morphine withdrawal for 1 week and different morphine dependent times(1 week, 2 weeks, 4 weeks) were established. The expression of BDNF and PSD-95 in hippocampal CA1 were identified with RT-PCR.The expression of BDNF and PSD-95 in hippocampal CA1 decreased in the withdrawn group with morphine dependence for 1 week as compared with that in normal saline (NS) group (P0.01), and it increased in the withdrawn group with morphine dependence for 2 weeks as compared with that in morphine-dependent group for 1 week (P0.05) but still decreased as compared with that in NS group (P0.01), and it decreased in the withdrawn group with morphine dependence for 4 weeks as compared with the other three groups (P0.01).The expression of BDNF and PSD-95 in hippocampal CA1 decreases in morphine-depended rats withdrawn for 1 week. Morphine withdrawal has a manifest harm in hippocampal CA1 region of rat.