There are four major categories of western drugs used to treat insomnia, namely barbiturates, benzodiazepines, non-benzodiazepines, and other drugs. The following four major classes of drugs are introduced: First, barbiturates are rarely used in the treatment of insomnia at present. Second, benzodiazepines are currently the most widely used sleeping drugs, these drugs can shorten the time to fall asleep, reduce wakefulness, increase the total sleep time, is a relatively good safety and tolerability of sleeping drugs, the main representative drugs are alprazolam, Valium, clonidine. Third, non-benzodiazepines, this type of drugs on behalf of zopiclone, zolpidem. These drugs have the advantages of fast onset, short half-life, no hangover symptoms the next morning, drug dependence and less rebound from discontinuation, etc. They are currently recommended as the first-line drugs for the treatment of insomnia. Fourth, other drugs, such as melatonin, anti-anxiety and depressants, are also effective for insomnia.