Abstract: This experiment is about the sensitivity of the flowering and fruiting of early rice to high temperature (35 ℃) injury. It was carried out in the phytotron. There is a stage of most sensitive to high temperature injury during the flowering and fruiting period in early rice. In other words, there is a stage when the injury caused by high temperature is most serious. But the sensitive stages to injury of empty grain, unfilled grain and kilograin weight are. different. The high temperature injury mainly results in the increase of the percentage of empty grain during the flowering of early rice. The stage most sensitive to high temperature, for the spikelet, is one day before the flowering; for the panicle, or the stand in the paddy field, one day before full bloom. It is possible to take measures for prevention of high temperature injury in time, if we know the stage most sensitive to high temperature, the clates of high temperature and the developmental stage of rice in paddy field.