Kernel-related traits， including kernel length， kernel width， and hundred kernel weight， are pivotal factors in determining maize yield. In this study， a recombinant inbred line （RIL） population derived from the maize inbred lines B73 and CML277 was utilized as the experimental material. Based on the high-precision genetic maps constructed through genotyping-by-sequencing （GBS） technology， nine kernel-related quantitative trait loci （QTL） were identified. The major locus qKW2.04 was precisely located on chromosome 2 using the inclusive composite interval mapping （ICIM） method， explaining 20.34% and 15.84% of the phenotypic variation on grain width and 100-grain weight， respectively. In addition， an F₂ segregating population was developed using the recurrent parent B73 and its introgression line （NIL-1041A） to further delimit qKW2.04. This locus was found with contribution due to two tightly linked kernel width major QTL， designated as qKW2.04-1 and qKW2.04-2， which were located in the marker intervals InDel23.32~umc1555 and InDel47.09~InDel57.06， explaining 22.45% and 12.22% of the phenotypic variation， respectively. The favorable allelic variations for both QTLs were contributed by CML277. Through the selection of recombinant individuals within the target region， qKW2.04-1 was finely positioned between molecular markers InDel26.76~InDel27.86 within a 1.1 Mb interval. This study provides new clues for elucidating the genetic basis of kernel-related traits and gene resources for high-yield molecular breeding in maize.