Maintenance of wakefulness test（ MWT） is of great value in evaluating the awakening ability of the daytime. It is mainly used to the evaluation of the awakening ability of a particular profession and to evaluate the therapeutic effect of excessive daytime sleepiness（ EDS） patients. This article reviews the monitoring methods， clinical application and research progress of MWT， and compares the difference between MWT and multiple sleep latency test（ MSLT）.