Abstract: A experiment was made to study root system development and drought resistance of sorghum and millet，The results showed that root system of sorghum and millet was enhanced evidently under drought conditions．The average root length of dry biomass of sorghum on the ground was 8m／g，and that of millet was 1lm／g．Their ability to utilize soil water in the depth of 0～100cm was significant，near the wilting point，Such main physiology indexes as photosynthetic rate，stomatal resistance and leaf moisture potential did not act obviously to the decreasing soil moisture．The indexes of sotghum could even keep stable in its experiment moisture range(14％ ～30％ of soil volumetric water content)，so sorghum has more drought tolerance and resistance than millet.