Abstract: Nitrate Reductase (NR) is a key enzyme for nitrate assimilation in plants. Through its catalytic reaction, it not only regulates nitrate reduction but also influences the carbon metabolism of photosynthcsis. Exploring additional physiological functions of NR. and understanding the functioning mechanisms will be of great significance both in theory and practice. The rapid developments of molecular biology makes it possible to understand the NR's physiological functions and the underlying mechanisms at the molecular level. Further, through the molecular approaches we may be able to know the relationship between nitrogen metabolism and other metabolic pathways, and also relationship between NR, NO and abiotic or biotic stresses. Research prospects on nitrate reductase.