A naturally-occurring lesion mimic mutant lm452 was identified in the progeny of the near iso-genetic lines derived from Xinong1376 × Kehan21. This study analyzed the development， physiological-biochemical characteristics， agronomic traits， and inheritance of lesion mimic phenotype in lm452. The lesions were initially visualized in the first leaf， with the color from white to tan， with striped and patchy appearance. With the development of plants， the number of lesions gradually increased from leaf to sheath. The lesions seem temperature/light sensitive， since leaves shaded can avoid or reduce their occurrences， and low temperature and strong light can enhance the occurrence. Gained from the results of physiological and chemical assays， the lesions were associated with burst of reactive oxygen species （ROS）， and reduction on soluble protein content and cellular viability. The 1000-kernel weight of lm452 was significantly lower than that of its sister line g451 under either field or greenhouse conditions. Genetic analysis showed that the lesion mimic trait of lm452 was controlled by a single recessive nuclear gene. Collectively， these results provided the foundation for isolation of the target gene and deciphering its molecular mechanism in future.