Abstract: 【Objective】 To carry out ggenetic analysis of the leaf width of maize and detection of major QTL controlling leaf in the hope of providing an important theoretical basis for breeding maize with ideal plant type. 【Methods】 In this experiment, the F_2∶3 family was constructed from the maize inbred lines B73 and Zheng 58 which were genotyped by liquid phase 48k probe capture technology and phenotyped in multi-environment trails for QTL mapping and genomic selection. 【Results】 The results showed that the leaf width displayed significant differences in genotype, environment, and genotype and environment interaction.The broad-sense heritability was 0.39.A total of 12 QTL distributed on chromosomes 1, 3, 4, 5, 8 and 10 were identified for leaf width.The phenotypic variation explained of each QTL ranged from 3.75% to 16.17%.Two loci, located on bin1.06 and bin5.01, were stable QTL detected in multiple environments.The QTL located on bin 5.01 was a major QTL, which could be used for fine mapping.When the number of SNPs reached 300 and the training population size reached 50%. 【Conclusion】 Leaf width is controlled by major polygenes, and genome selection can accelerate the efficiency of leaf wide traits.