Abstract: Effects of drought stress on the chlorophyll fluorescence parameters and photosynthesis rate in leaves of three asparagus bean [Vigna unguiculata ssp．sesquipedalis(L．)Verd.] cultivars with different tolerance to drought stress were investigated．The results showed that the biomass，net photosynthetic rate(Pn)of seedling greatly decreased，and the plasmalemma permeability of seedling leaves significantly increased drought stress．At the same time，the chlorophyll fluorescence parameter(Fo，Fv／Fm，φPSⅡ and qP)were also affected by drought stress，which showed a correlation with drought tolerance．The chlorophyll fluorescence parameters can be used as convenient indexes for evaluation of the drought tolerance of asparagus bean cultivars．

Key words: Vigna sesquipedalis, drought stress, chlorophyll fluorescence parameter, correlation