The nucleotide and amino acid sequences of starch synthase gene（SS） of six plants（Solanum tuberosum，Impomoea batatas，Triticum aestivum，Sorghum bicolor，Cucurbita moschata，Oryza sativa） were analysed using bioinformatic method and the physical and chemical properties and functional domains were predicted. The results showed that SS cDNAs of S. tuberosum，I. batatas，T. aestivum and S. bicolor contained methylation site. The average length of SS was 1 847 bp and the average length of the open reading frame was 877 bp. The start codons were all ATG，and the stop codon consists of 3 kinds. The average number of amino acid residues was 286，and the average relative molecular mass was 31 915.88，the average isoelectric point was 8.2645，the average charge was -0.598 1 in neutral solution. The average number of hydrophilic amino acid was 63，and the average number of hydrophobic amino acid was 102. All the SS of these six plants had two transmembrane domains.The irregular curl and extension chain were found the main component of all the SS secondary structures. Throngh starch synthase by phylogenetic analysis，T.aestivum was similar with S. bicolor in degree of evolution ，but far away from C. moschata.
