Based on field experimental data gained at automatization greenhouse in water-saving park of Hohai University, character of water demand and yield of space-time deficit irrigation for hot pepper in greenhouse was studied. The results indicated that soil water content at two sides of furrow fluctuated with the introduction of the alternate partial root-zone irrigation during regulated deficit irrigation at some stage of hot pepper, which could enhance the adsorptive ability of root system. Under the condition of abundant water supplying, the maximum water consumption was at vigorous growing stage, followed by seedling stage and bloom and fruit setting stage, relatively small at later fruit-bearing stage, which respectively accounted for 39.96%, 22.91%, 19.34% and 17.19% of total water consumption. The effects of drought stress and irrigation model at different growing stages on evapotranspiration were significant. In order to attain high yield and high water use efficiency (WUE), moderate uniform deficit irrigation should be introduced to two sides of root-zone at seeding stage, re-water at bloom and fruit setting stages, uniform deficit irrigation and alternate partial root-zone irrigation should be adopted at vigorous growing stage and later fruit-bearing stage, respectively. 