| In order to know the effect of soil moisture condition during different growth stage to the tomato yield, the whole growth period of tomato has been divided into five growing stages as seeding(X1), beginning flower and fruit setting(X2), early fruit growth(X3), rapid fruit expansion(X4) and quality development stage(X5), according to the development situation of tomato first fruit. Using the composite quadratic general regressive rotation design with five factors, has carried out the pot experiments and set up the regression model of tomato yield to soil water content, and analyzed the coupling effects of each single factor and two interactive factors. Based on the Jensen and Blank model, has analyzed the sensitivity of yield to water consumption during each growth stage. The results showed that: When the soil water content was at the middle level in other growth stages, the tomato yield has showed an upward trend with the increase of soil moisture during the early fruit growth, rapid fruit expansion and quality development stage, and showed a downward parabolic change with the increase at the beginning flower and fruit setting stage and no any change at the seeding stage. The interactive function of the soil moisture during the beginning flower and fruit setting, early fruit growth, rapid fruit expansion and quality development stage total represented to promote the tomato yield increasing. The sensitivity of tomato yield to water deficit in each growth stage was down successively from X5, X3, X2, X4, X1. The sensitivity indexes related Jensen Model were 0.1658, 0.1275, 0.0941, 0.0448 and -0.1813. The maximal tomato yield per plant could be reached 1406.04 gram when the relative soil water content of were 50％～60%, 90％～100%, 90％～100%, 90％～100%, 90％～100%, respectively at the X1, X2, X3, X4, X5 stage. The comprehensive analysis has indicated to guarantee irrigation at the X3, X5 and X4 stages, reduce irrigation at the X1 stage and appropriately control irrigation at the X2 stage could be effectively increased the tomato yield. |