Abstract: In order to study effects of drought stress on Shatangju tangerine（Citrus reticulate‘Shatangju’）nutrition status and its relations with flowering，potted culturing experiments were carried out and multi-factorial design was applied with water stress duration（0，2，4，6，8 weeks）and nitrogen fertilization level（5 g compound fertilizer and 5 g compound fertilizer plus 6 g urea per pot）as factors. It was found that nitrogen and potassium levels increased after four weeks of drought stress，compared with control，while nonstructural carbohydrates decreased. Citrus phosphorous content was not significantly influenced. The relative content of nutrition was also affected by drought stress，with citrus C/N and P/N being decreased relatively compared with control. The critical time point for nutrition differentiation was at about four weeks after the initiation of drought stress，which was also coincident with the critical inducting period in flowering exhibition. Flower numbers per shoot had positive correlations with nitrogen and potassium content，but negative correlations with C/N. Phosphorous content did not have significant correlations with flowering. Shatangju tangerine did not show any flowering under normal water condition no matter what the nutrition status was，but nitrogen，potassium and C/N had good correlations with flowering properties when drought stress was more than four weeks.

Key words: citrus, Shatangju tangerine, drought stress, nutrition, flowering