Abstract：The development of genomic SSR markers is a difficult and time-cost work. EST database has become a rich source for in silico identification of SSRs and provided a cost-effective，labor-efficient approach for SSR marker development. Firstly，2 204 ESTs of tree peony (Paeonia Suffruticosa Andrews.) were downloaded from the database of NCBI and some redundant sequences were removed and 1 658 non-redundant ESTs were obtained. Subsequently，MISA，a web tool for SSR hunting，was used to analyze the SSR motifs in the EST sequences. The results showed that a total of 1 111 SSRs were detected which distributed in 901 ESTs，with the frequency for the non-redundant ESTs being 67.00 %，the average distribution distance of the EST-SSRs were about 1 004 bp. Among the different SSRs motifs，mononucleotide repeats were most abundant (89.38%)，followed by dinucleotide (6.67%) and trinucleotide repeats (3.78%). Distribution of hexanucleotide repeat and tetranucleotide repeat were very few，and there is no existance of pentanucleotide. A/T was the most frequent repeat motif and accounted for 87.76% in all SSRs. Among all SSRs，SSRs repeated 8 to 30 times accounted for 85.15%，and SSRs which was 26 to 31 bp long accounted for 49.86% in total.