Changxuan3S was thermo-sensitive genic male sterile (TGMS) rice(Oryza sativa L.) with eui gene selected from Peiai64S irradiated by 350 Gy60Co γ-ray. To study the effects of temperature on panicle exsertion for Changxuan3S, Changxuan3S was taken as material and Peiai 64S as control. The results showed that the increasing rate of the elongated uppermost internodes was slow from the 12th day preblooming to the 4th day preblooming, and 0day (anthesis) to the 3rd day after anthesis under the condition of constant 24 ℃, the daily mean increasing length had no obviously difference between Changxuan 3S and Peiai64S. But the increasing rate of the elongated uppermost internodes for Changxuan 3S was faster, and was 2.1 times greater than that of Peiai 64S from the 4th day preblooming to 0 day (anthesis). During the thermo-sensitive period, when Changxuan 3S was treated with the condition of constant 22, 24, 26, 28 ℃, the panicle exsertion was positive number under the treatment 22, 24, 26 ℃, respectively, so that panicle enclosure in Changxuan 3S disappeared, and the lower the temperature treated, the longer the panicle elongation was, while the panicle was enclosed at temperature 28 ℃. Cytological studies on Changxuan 3S showed that the uppermost internodes elongation was due to the increase of cell number and elongation, and the elongation of the later was more significant. But also, the number of outermost and innermost parenchyma cell in uppermost internodes reduced, and the cell length shortened along with increasing temperatures.