Abstract: Nicosulfuron was a broad-spectrum, inner-absorption conducting herbicide that has been widely used in the maize seedling stage. Given that different corn lines showed significant difference in the nicosulfuron resistance, severe injuries of some corn lines caused by nicosulfuron have been repeatedly reported. The action mechanism of nicosulfuron, the identification of nicosulfuronresisitance in different kinds of corns and the genetic mechanism of maize tolerance to nicosulfuron were reviewed, and several problems have been pointed out, for example, fine mapping of the antinicosulfuron gene in maize was not clear, the investigation of the nicosulfuron metabolic mechanism was rather difficult, and etc. It has been proposed that future research should focus on the excavation of the endogenous anti-nicosulfuron gene and the ultimate realization of the gene conversion so as to improve the nicosulfuron-resistance of corn lines.