In order to explore the genetic mechanism of wheat seminal root formation and growth， 198 wheat natural cultivars growing in the Huang-Huai Area were investigated in this study. The total first grade branch number， branch density， length， surface area， volume and average diameter of the radicle were examined using 21 days old seedlings in the hydroponic culture. Q+K mixed linear model， in conjugation with the genotyping results by the 660K gene chip， was used to conduct genome-wide association analysis （GWAS） at radicle traits， followed by functional annotation and candidate gene mining of significant and repeatedly-detected association sites. At the six radicle growth traits， a continuous and normal or nearly normal distribution were observed， with coefficient of variation of 5.56%-22.10%. A total of 136 significant association sites were detected. They were distributed on the chromosomes except 7B， each of which could explain 5.10%-13.60% of phenotypic variation. Thirteen significant pleiotropic sites were identified from those 136 sites. Based on the annotation， 16 candidate genes that may be related to radicle growth were found， such as TraesCS4A01G023100， TraesCS1B01G294400， TraesCS4A01G006200. These genes were proposed to be involved in the formation of wheat radicle root system by regulating DNA topoisomerase， ubiquitin-conjugating enzyme E2， phosphoinositide phosphatase family protein and so on. The results of this study provided a reference for the construction of wheat root regulation network， as well as the optimization of root architecture and function.