Genetic structure of parental inbred lines of the common maize varieties was analyzed using 56K maize gene chip,and heterosis modes of parental inbred lines of the main maize varieties were analyzed,so as to provide guidance and reference for maize breeding.The results showed that a total of 35 261 high-quality single nucleotide polymorphism(SNP) markers were obtained from 56 000 SNPs,the average of minimum allele frequency (MAF) was 0.28,the MAF of 12.56% of the SNP markers were 0.45—0.50,the polymorphism level was high.Polymorphic information content(PIC) was 0.10—0.50,with an average of 0.37.The results of cluster analysis showed that,five groups were divided,of which,group Ⅰ was mainly BSSS germplasm,which was represented by PH6WC;group Ⅱ mainly contained PH4CV,male parents of hybrid DK517 and DH605 and so on; group Ⅲ contained Reid, P group germplasm and European male parents;group Ⅳ contained domestic lines,such as Zong 3 and Zong 31;group Ⅴ contained classic SPT germplasm,Suwan and CIMMYT tropical germplasm.At the same time,the parental SNP differences of 16 maize hybrids were analyzed,and a total of 7 615 polymorphic sites and 7 592 conserved sites were selected.