A hydroponic experiment was conducted to study the effects of the exogenous auxin (3 -indole acetic acid, IAA) on rice roots (root length, root weight), shoot growth (height and biomass) and chlorophyll content in the rice seedling stage. The results showed that the root growth in rice seedling was no significant difference when treated with different concentrations of IAA from 1d to 5d. When treated for 10d, root length of rice for the treatment of 1 μM IAA increased by 41.1% (p<0.05), while plant height, root and shoot weights were not significantly affected; root weight for the treatments of 10 μM, 25μM and 100μM IAA increased by 39.1%, 25.9% and 17.8% (p <0.05), respectively; plant heights and shoot weights reduced significantly from a rate of 16.0% to 20.7%, and from 20.0% to 36.7% with increasing IAA concentration from 25μM to 100 μM IAA, respectively, as compared with CK. As a result, the ratios of root to shoot increased with IAA concentration increases. Moreover, contents of chlorophyll a, b and total chlorophyll for treatments with IAA(1μM-75μM) increased by more than 30% (p <0.05) compared with the control. Therefore, applying IAA with a suitable concentration in rice seedling stage can promote rice growth and increase chlorophyll content, which is beneficial to promote photosynthesis efficiency and improve rice yield