Abstract: Water logging stress experiment was conducted at heading flowering stage and milk stage of hybrid rice Xiang Feng You 103Sensitivity of hybrid rice to water logging stress at different growth stages was analyzed，through comparing green leaf number，aerial root，lodging conditions and yield components before and after different flooding treatments The results showed that green leaf number was extreme significant negative correlation with the depth of  water logging The ratio of aerial root stem was negative correlation with flooding depth and positive correlation with flooding duration Aerial root was more as lower the stem nodes，especially at heading flowering stage Stem lodging occurred at heading flowering stage，and there was a significant positive correlation between the percentage of stem lodging and water logging duration Root lodging occurred at milk stage，and it was worse with water logging deeper and longer The sensitivity of hybrid rice to water logging stress at heading flowering stage was more than that at milky stage Yield was failure with water logging stress for 5 days at this stage The research results could be used as evaluation standard of flood disaster to hybrid rice

Key words: Rice, Water logging stress, The number of green leaves, Aerial roots, Stem lodging, Root lodging, Yield factors