Abstract: The experiments were carried out in growth clamber to investigate the effects of high temperature stress during heading and flowing period on pollen and seed setting characters using two rice lines including heat-tolerant line Teqing (TQ) and heat-sensitive line YIL106. This study showed that the stained pollen rate, the pollen germination rate and the pollen grains on the stigma, the coefficient of anther dehiscence and the seed setting rate of rice under high temperature stress were lower than those under conventional temperature condition, the decrease scope of YIL106 were higher than that of Teqing. In this study, the significant difference was found between Teqing and YIL106, indicating that YIL106 was more sensitive to heat than TQ.