Abstract: The study aims to analyze the genetic diversity and divide the population structure of some maize inbred lines in Gansu Province. Genetic diversity of 148 maize inbred lines was analyzed with 66 pairs of core SSR primers and fluorescent SSR-PCR technology in automatic DNA analyzer. The population structure was analyzed by distance-based cluster and model-based cluster methods. Totally in the 148 lines, 279 alleles were detected with an average of 4.2273, ranged from 2 to 8 per locus with 66 pairs of SSR primers. The average polymorphism information content (PIC) and marker index (MI) were 0.4879 and 2.1808, respectively. All the 148 inbred lines were grouped into NSS group and SS group by model-based cluster method, and were divided into five groups by distance-based cluster method. These 5 groups could be incorporated into SS group and NSS group according to the commonly used test inbred lines. Results showed that the clustering groups were consistent with the basic materials of pedigree information. In conclusion, part of maize inbred lines in Gansu Province were transforming into two relatively independent groups in breeding practice, the genetic diversity level between the two groups had certain differences.