In this study， 134 maize inbred lines were used as experimental materials to identify phenotypic variations at nine root traits at seedling stage， followed by the genome-wide association study （GWAS） using FarmCPU model based on 44935 SNP markers. The results showed that the phenotypic variations at nine root traits ranged from 10.86% to 55.96%， and the correlation between most phenotypes reached a highly significant level （P<0.001）. The correlation coefficient between lateral root length and total root length was the highest （0.996）， followed by that between the number of lateral roots and total roots （0.993）. A total of 32 significantly associated SNPs were identified （P value arranged from 1.01e^-11 to 9.74e^-5）， with phenotypic contribution rates ranging from 0.54% to 22.34%. Four， eight， three and nine significant SNPs were detected for main root length， total root length， maximum root length and lateral root length， respectively. Ten， seven and one significant SNPs were detected for total root number， lateral root number and adventitious root number， respectively. Fourteen SNPs were identified associating with multiple root traits. Twelve significant association sites were located within the intervals where root-related QTL （Quantitative trait locus） were reported. Forty-nine root-associated candidate genes were annotated， including formerly-identified GRMZM2G028386 （ABI4）， GRMZM2G135713 （PUB23）， GRMZM5G870592 （MYB98）， GRMZM2G156861 （LOX1）， GRMZM2G160005 （AUX16）， GRMZM2G126936 （NAC2） and other important root candidate genes. Thus， this study provided reference for future cloning genes related to root development and analyzing the molecular mechanisms of root development in maize.