Abstract: Objective To abyss the changes on the whole night polysomnography(PSG)in patients with depression disorder and study the difference between patients and normal subjects.Methods The whole night PSG was recorded from 20 patients with depression,and 20 normal subjects with sleep instrument.Results Compared with normal subjects,depression patients have prolonged incubative stage of sleep,reduced sleep maintenance,reduced slow wave sleep and increased density of REM.Conclusion We consider that the depression patients usually fall asleep difficulty,easy to awake,or awake earlier.The characteristic changes of polysomnography in depression patients are the overacfivity of the BEM sleep.The incubative stage of REM sleep reduced andthe density of REM increased.The reasonmay be the reduce of the 5-HT/NE transmission and the increave of cholinergic transmission.We consider that the characteristic changes of REM sleep in depression patients have important clinical significance as the evidence of the diagnosis of depression.