Abstract: On the basis of analyzed the variation of soil water content in different treatments, the effect of water treatment on vegetative, reproductive growth, physiological mechanism was discussed respectively. Meanwhile, the difference of water use efficiency from different water treatments was analyzed. The main conclusion includes four aspects. Firstly, the soil water content from 60cm to 100cm was reducing in whole growth period, which is more obvious in water stress treatment, namely the variation of soil water content is 13%~21%; Secondly, the effect of soil water on vegetative growth is positive, but the effect of soil water on reproductive growth is not obvious; Thirdly, the cellular liquid concentration in water stress treatment is higher than that in high water treatment, but the stomatal conductance in water stress treatment is lower than that in high water treatment; The last, if the soil water content was not lower than 70% after reproduced, it was adapt to tomato.