The effects of different irrigation patterns at panicle formation stage on yield in rice were studied.It showed that the irrigation with 10cm of water at panicle formation stage increased yield by 3%~5%and 13%~20% than with 5cm of water in normal year and in cold year, respectively. But the irrigation with 10cm of water +20cm of water made a yield increase of 20%~30%. The efficiency of 10cm irrigation was better than that of 20cm.