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Stomatal conductance is the basis of photosynthesis-transpiration couple.This study was conducted to investigate the daily variation of stomatal conductance of rice and its response to PAR under five different flooding conditions by controlling water level.The experiments were conducted in evaporation-infiltration-test-pit of the Water-saving Park at Hohai University for two consecutive years in 2012 and 2013.The results indicated that the daily variation curve of stomatal conductance varied with daily variation curve of PAR.The daily variation of stomatal conductance would show an M-curve, but on condition that PAR at noon was consistently larger than 600 μmol · m-2 · mo1-1 or increased rapidly in a short time.The stomatal conductance under flooding condition generally has a lower value than CK, and its peak value is also lower than CK (5%-15%).The reason was that waterlogging delayed the normal opening and closing of stoma.The relation between stomatal conductance and PAR featured a quadratic curve.The stomatal conductance gradually decreased in the case of small amplitude of PAR for the whole growth periods of rice.Waterlogging will reduce the stomatal conductance in tillering period, but suppress the photosynthetic depression.Waterlogging will hinder the normal opening of stoma and intensify photosynthetic depression as PAR>450 μmol · m-2 ·mol-1 in heading to flowering period.The parameters had an important practical significance in optimization of irrigation-drainage management policy in each growth stage of rice.