Abstract:The changes in fertility and physiological activities of rice Annong S-1 and Hengnong S-1 were studied under different day length and temperature conditions. The results showed that, in long day or short day, the high temperature (31℃/28℃) induced male sterility of Annong S-1 and Hengnong S-1, the low temperature (24℃/22℃) induced them fertile. Under high temperature condition, ATP contents in their floscules and anthers were decreased obviously, the rates of respiration of the floscules and the anthers were declined gradually.