To broaden the genetic basis of maize inbred lines and accelerate the integration and utilization of excellent foreign germplasm, SSR molecular markers were used to analyze genetic diversity of 122 maize inbred lines from the United States, Serbia and China. The results showed that a total of 115 alleles were detected by 29 polymorphic SSR markers, with an average of 3.97 alleles per SSR primer pair and with an average polymorphic information content (PIC) of 0.50, revealing high genetic diversity among the inbred lines. The observed heterozygosity (Ho) was only 0.03 indicating that the tested lines have high genetic stability and homozygosity. Among the four groups of American SS, American NSS, Serbs and Chinese inbred lines, the allele number (3.55) and Shannon's information index (0.93) in the American NSS group were the highest and the number of effective alleles (2.37) in the Serbs group was the highest indicating that the groups of American NSS and Serbs have higher genetic diversity than the other two groups. The genetic distances among the four groups ranged from 0.1403 to 0.4695 with being the largest genetic distance between American NSS and Chinese inbred lines and with being relatively smaller (0.1419，0.1403) between American NSS and American SS or Serbs. The genetic consistency of the four groups ranged from 0.7439 to 0.8669. The higher genetic identity among the groups of American NSS, American SS and the Serbs indicated that the genetic exchanges between American and Serbia inbred lines are frequent and their genetic relationship is relatively close. The clustering analysis showed that 122 maize inbred lines could be divided into 9 major groups. Two groups of American SS and NSS were clearly distinguished. The American SS was further divided into 2 subgroups (Ⅰ and Ⅸ). The American NSS was divided into six subgroups (II-VII), while the inbred lines from Serbia are dispersed in the NSS groups. The results of this study provide a reliable basis for the rational utilization of maize inbred lines from the United Statesand and Serbia.