Abstract: Tandem repeats（TRs） exist widely in the genomes of eukaryotes, which influence inheritance and evolution of organisms by affecting the spatial structure of chromatin and participating in the processes of gene expression. The paper analyzed the 1～50 bp repeating units of TR characteristics in Arabidopsis lyrata genome. The results showed that the highest densities were in 5’UTR and promoter regions（8 757 bp/Mb and 8 430 bp/Mb, respectively）, and the lowest density was in CDS region（2 406 bp/Mb）. T/A bases in single nucleotide repeat motifs showed the highest density in the genome, and dinucleotide repeat units were the highest in 5’UTR, while CDS mainly contained trinucleotide repeating units. The differences of TR characteristics among different regions were closely connected with gene expression and regulation. The study would deepen our understanding on TR characteristics and functions in plant genomes, and would provide references on TRs in gene expression and plant genome evolution.