The invention provides a maize single panicle weight main effect QTL, as well as an acquisition method and application thereof. The QTL comprises qEW-1, qEW-2, qEW-3, qEW-4 and qEW-5. The method comprises the following steps: configuring cross combination by taking a high-yield early-maturity maize inbred line SG5 as a female parent and a maize inbred line SG7 with relatively poor yield trait as a male parent, and constructing an F2 genetic group of the cross combination; performing GBS sequencing-basing typing on the F2 genetic group, and performing genotyping by combining differential SNP validated based on SG5 and SG7 parents; investigating the yield trait of single F2 panicle, performing QTL analysis on the F2 single panicle yield trait by utilizing a winQTLcart2.5 software composite interval mapping method, and analyzing the chromosome region of the main effect QTL and the genetic effect. According to the method, a theoretic base is provided to excavating and controlling the maize single panicle weight main effect QTL and linked marker, a molecular marker closely linked with the target QTL is acquired, and foundation is laid to maize single panicle yield trait QTL candidate gene prediction, cloning and molecular mark assisted breeding.