There is a significant potential to increase yield of maize (<i>Zea mays</i> L.), a global major crop, in rain-fed condition in semi-arid regions, since the large yield gap is mainly caused by frequent droughts halfway the crop growing period due to uneven distribution of rainfall. It is questionable if irrigation systems are economically required in such a region since total amount of rainfall generally meet the crop requirement. This study therefore aimed to quantitatively determine the effects of water stress during jointing to filling stages on root and shoot growth and the consequences for maize grain yield, above- and below-ground dry matter, water uptake (WU) and water use efficiency (WUE). Pot experiments were conducted in 2014 and 2015 with a mobile rain shelter. The experiments consisted of three treatments: (1) no water stress; (2) mild water stress; and (3) severe water stress. Maize yield in mild water stress across two year was not significantly affected, while severe stress reduced yield by 56 %. Water stress decreased root biomass slightly but shoot biomass substantially. Mild water stress decreased root length but increased root diameter, resulting a no effect on root surface area. WU under water stress was decreased, while WUE for maize above-ground dry matter under mild water stress was increased by 20 % across all years, and 16 % for grain yield WUE. Our results demonstrates that irrigation systems in studied region might be not economically necessary because the mild water stress does not reduce crop yield. The study helps to understand crop responses to water stress during critical water-sensitive period and to mitigate drought risk in dry land agriculture.