This study used homologous sequence cloning method to clone the full length of sucrose phosphate synthase gene in Dendrobium officinale and induce prokaryotic expression.Results were as follows:(1)The cDNA is 3 502 bp in length containing an open reading frame of 3 186 bp encoding 1 061 amino acids.The GenBank accession number is JF423929.On the amino acid sequence level,this gene shows the highest similarity (93％) with SPS gene of O.goldiana.The similarity of SPS gene were higher than 60% with other plants.(2)The gene was expressed in E.coli with molecular mass of 118.7 kD,which was consistent with the speculation of Biotech.(3)Secondary structure includes helix,beta-folding and coil,which is a hydrophilic,transmembrane and unstable proteins.There are two function structure domains which are sucrose synthesis functional domain and glycosyl transfer function domain.This study provides the theory basis for research the gene spatio-temporal expression and function,polysaccharide synthesis mechanism and metabolism path in D.officinale.