Insomnia is one of the common symptoms of depression. 61.2% of women and 68.6% of men with depression have insomnia. In the general population, 20% of insomniacs have depressive symptoms. Insomnia includes difficulty falling asleep, shallow sleep and early awakening. The main symptoms of insomnia in depressed patients are early awakening, difficulty in falling asleep after waking up, recurrence of unpleasant past events in the mind or anxiety about the future, or repeated awakening during sleep or excessive dreaming. Patients with depressive insomnia are mostly accompanied by other depressive symptoms such as depressed mood, decreased interest, slowed thinking, and reduced behavioral activities, etc. Some depressed patients have only insomnia as the main complaint. The normal sleep structure of depressed patients is disrupted, and the structure of polysomnogram is changed: sleep efficiency is reduced, sleep persistence is disrupted; deep sleep is reduced; REM (rapid eye movement sleep phase) latency is shortened, REM ratio is increased, and density is increased. Insomnia is not only one of the symptoms of depression, but also one of the factors leading to the occurrence of depression. Insomnia can aggravate depression and slow down the recovery process of depression, so the treatment of insomnia can promote the remission and recovery of depression. The treatment of simple insomnia is currently dominated by benzodiazepines in clinical practice, but because these drugs cause dizziness, drowsiness and fatigue in patients, are easily tolerated and cause dependence, they are gradually being replaced by new generation drugs (such as zolpidem, zopiclone and zaleplon) and melatonin receptor agonists. For patients with depression with insomnia, new antidepressants can be used (to kill two birds with one stone. Antidepressants improve sleep quality by increasing the patient’s slow-wave sleep, increasing sleep efficiency, and improving sleep architecture while treating depression. In addition, psycho-behavioral therapy such as relaxation training, cognitive-behavioral therapy, and biofeedback therapy can be used as an adjunct to improve depression and insomnia.