【Object】The experiment was conducted to study the physiological effects，grain yield and yield components of Guiliangyou 2 under water stress and re-watering to get water stress threshold value in order to provide reference for its water-saving irrigation cultivation. 【Method】By using pot experiment， CK （normal irrigation， NI） and four water stress treatments viz.， T1（micro-slight stress， soil water content accounting for 90%-100% of saturation moisture content）， T2（slight stress， 80%-90% of ）， T3（moderate stress， 70%-80%） and T4（serious stress， 60%-70%）， were designed for super rice Guiliangyou 2 at booting and grain filling stages. The physiological indices of leaf were measured after 15 days of water stress and 10 days of re-watering， and grain yield was measured at mature stage. 【Results】As compared with the control， malondialdehyde （MDA）， soluble protein， soluble sugar， and chlorophyll relative content （SPAD value） in rice leaves were increased after  15 days of water stresses at booting stage， and all of them were found the highest （7.53 μmol/gFW， 36.55 mg/gFW， 11.30 mg/gFW and 39.08） in treatment T4， which significantly increased by 21.84%， 57.00%， 61.20% and 20.36%. The above-mentioned indices were found to be the lowest in T1 treatment. After 10 days of re-watering at booting stage， it found that MDA content of treatment T2， soluble protein and soluble sugar contents of treatment T3 and chlorophyll relative content of T4 treatment had the highest increases by 16.09%， 54.23%， 33.96% and 11.31%. The proline content of leaf in T2 treatment was higher than other treatments after water stress and re-watering at booting stage At grain filling stage， after 15 days of water stress， the MDA and chlorophyll relative content in leaves of different treatments increased firstly and decreased at later along with increasing extent of water stress， and the highest one presented in T2 treatment. The soluble protein and sugar contents showed gradual increase and reached the highest in T4 treatment. After 10 days of re-watering， MDA， chlorophyll relative content， soluble protein and soluble sugar in leaves presented change trend of increase first and then decrease in different treatments. These indices of T1 treatment were a little higher than the control but lower than the other treatments. With increase extent of water stress， the proline content in leaves decreased constantly. The yield and its component factors of Guiliangyou 2 presented the best in T1 treatment after water stress at boot stageand grain filling stage， respectively， and the yield increased by 18.15% and 10.92% compared with the control， while the other treatments showed worse comprehensive performance than the control. 【Conclusion】The micro-slight water stress can enhance drought resistance of Guiliangyou 2 and get better compensatory effects after re-watering. Guiliangyou 2 was more sensitive to water stress at booting stage than grain filling stage.