Obstructive sleep apnea is a common disease，the prevalence of which is increasing year by year，and the nocturnal intermittent hypoxia triggered by it is closely related to a variety of adverse health outcomes，therefore，it is a hotspot to search for a simple，reliable and comprehensive index to assess intermittent night hypoxia in recent years. In this paper，we summarized the different evaluation methods of the indexes related to nocturnal intermittent anoxia，including the frequency（oxygen saturation decline index），duration（time when oxygen saturation is below 90% and saturation damage time），and hypoxia amplitude（lowest oxygen saturation，oxygen saturation decline amplitude），etc，and comprehensive assessment indicators such as hypoxic load，hypoxic load index，hypoxic load，and sleep-disordered breathing index，etc.