The changes of seedling morphology, leaf photosynthesis and fluorescence parameters under soil water deficit and excess conditions were studied by potted plants. The results showed that under water stress, the leaf chlorophyll decreased significantly, the stomatal conductance（Gs） decreased, and the net photosynthetic rate（Pn） decreased significantly, accompanied by the decrease of light saturation point（LSP） to maintain the body’s metabolic balance. The initial fluorescence（Fo） and variable fluorescence（Fv） increased under water stress, while the electron transfer rate（ETR） and photochemical quenching（qP） decreased to improve the stability of the fluorescent metabolic system.