A natural lesion mimic mutant lm452 was found in the progeny of near iso-genetic lines built by Xinong1376 and Kehan21. This study analyzed the development, physiological-biochemical characteristics, agronomic traits, andSinheritance of lesion mimic in lm452. The results show that the lesion initially occurred in the first leaf, and onset parts were randomly; the color of lesion change from white to tan, with striped and patchy apperance. With the development of plants, the number of lesions gradually increased, and spread from leaf to sheath. The severity of lesion is affected by temperature and light; shading can avoid or reduce the occurrence of lesions. Low temperature and strong light can aggravate the spread of lesions; the results of physiological and chemical assays indicate that the formation of lesions is accompanied by the production of reactive oxygen species (ROS), decreased soluble protein content, and decreased cellular viability. The 1000-kernel weight of lm452 was significantly lower than that of sister line g451 in both fields and greenhouse. Genetic analysis showed that the lesion mimic trait of lm452 was controlled by a single recessive nuclear gene. Above results provide the foundation for cloning and molecular regulation network mechanism analysis of the target gene.