Abstract: Short photoperiod-low temperature induced male sterile rice is a new germplasm, whose fertility alteration characteristic is contrary to that of long photoperiod and high temperature induced male sterile rice.Compared with that of Yid1s sowed under natural conditions by stages,the fertility alteration of Yid1s was observed under simulated short photoperiod treatment. The results showed that the photoperiod-sensitive stage of Yid1s occurred from differentiation of rachis primordia (phase Ⅰ) to secondary rachis-branch and spikelet primordia (phase Ⅲ).The panicles induced by appropriate short daylight treatment at photoperiod-sensitive stage tended to be completely sterile under normal temperature,but the sterile effect was weakened under high temperature. The pollen fertility of Yid1s was reduced under high or low temperature. The temperature-sensitive stages of Yid1s based on the analysis of the effects of high and low temperature on fertility were basically identical,i.e.,from pollen mother cell formation (phase Ⅴ) to single nucleus (phase Ⅶ).