Objective：To investigate the effects of various degrees of rapid eye movement （REM） sleep deprivation （RSD） and sleep recovery on cognitive function （learning and memory） and expression of brain-derived neurotrophic factor （BDNF） in the rat hippocampus. Methods, Male SD rats were divided into 8 groups （n= 12）： blank control group （with normal sleep）, environmental control, RSD 1 d, RSD 3 d, RSD 5 d, RSD 7 d, recover sleep 6 h after 7 d RSD （RS 6 h）, and recover sleep 12 h after 7 d RSD （RS 12 h）. The modified multiple platform method （MMPM） was used to establish sleep deprivation model in rats. The cognitive functions of rats were tested by Y-type maze. The hippocampal BDNF mRNA and protein levels were detected by real-time PCR and immunohistochemical method. Results： The failure reaction times of all RSD groups and the 2 RS groups were significantly more than those in control group and environmental control group （P~0.05）. Compared with the control group, the total reaction time in RSD 1 d, 3 d groups was significantly lower （P〈0.05）, but that of RSD7 d group was significantly higher （P〈0.05）. Compared with the blank control group, expression of BDNF mRNA was significantly increased in RSD 1 d group （P〈0.05）, and reached the peak in RSD 3 d group. The protein expression of BDNF in CA1, CA3, and denatae gyrus areas of RSD1 d, 3 d groups and in the denatae gyrus area of RSD5 d and RS6 h groups was significantly higher than that of blank control group （P〈0.05）. Conclusion： Short-time RSD can lead to decrease of learning and memory ability, and recovery of sleep can partially improve their ability. The increase of BDNF expression may compensate the result of sleep deprivation and protect the cognitive function. However, as the prolongation of deprivation time, the compensation may become invalid