Water　stress　is　one　of　most　common　stress　factors　for　vegetation.　It　can　reduce　cell　water　potential　and　stomatal　conductance,　thus　may　threaten　the　process　of　photosynthesis.　Moreover,　it　can　be　noninvasively　detected　by　using　chlorophyll　fluorescence,　which　is　considered　as　the　proxy　of　photosynthesis　due　to　its　sensitive　to　physiological　change.　However,　chlorophyll　fluorescence　can　be　easily　influenced　by　various　factors,　such　as　water　stress,　temperature,　chlorophyll　content,　leaf　and　canopy　structure.　As　a　consequence,　the　relationship　between　chlorophyll　fluorescence　and　water　stress　is　significantly　complicated.　Thus,　the　study　is　focused　on　the　rationale　of　chlorophyll　fluorescence　and　its　application　in　detecting　water　stress.　Firstly,　the　origin　of　chlorophyll　fluorescence　in　the　view　of　photosynthesis　was　briefly　introduced.　Then,　influence　factors　including　chlorophyll　content,　leaf　and　canopy　structure,　ambient　factors　that　affect　chlorophyll　fluorescence　were　analyzed.　Furthermore,　we　summarized　the　application　of　chlorophyll　fluorescence　in　detecting　water　stress.　Finally,　based　on　the　above　clarification,　we　proposed　a　new　strategy　of　the　application　of　chlorophyll　fluorescence　in　water　stress　detecting.　©　2017,　Peking　University　Press.　All　right　reserved.