Abstract:This paper concerns with the studies of respiration intensity (RI) and cyanide resistant respiration intensity (CRRI) of young shoot of hybrid rice and their parents. The results show that both heterosis of RI and CRRI are almost negative, there are significant positive relationships between RI and CRRI of hybrids and that of their midparents, a significant positive relationship between difference of CRRI of hybrids and their midparents and that of their male and female parents, but no significant negative relation-ship between difference of RI of hybrids and their midparents and that of their male and female parents. We suggested that RI and CRRI of hybrids can be predicted from its midparent, CRRI is probably as the physiological parameter of hybrid rice heterosis predicting.