A Lactobacillus plantarum (LpS2) that was found to produce a large amount of γ-aminobutyric acid (GABA) was isolated from yellow serofluid, a bean curd byproduct in China. a) Glutamate decarboxylase (GAD) gene from Lactobacillus plantarum LpS2 was Cloned and amplified by PCR technology. Then, we predicted its amino acid composition, physicochemical property, signal peptide and advanced structure by on-line analysis tools and software. b) last analysis results showed that the amplification of gene nucleotide sequences have a very high homology with lpgad B reported in NCBI gene sequences, and the deduced amino acid sequences homologies were as high as 99%.The length of gene sequence was 1363 bp and coded 453 Amino acids. GAD relative molecular weight of theoretical prediction and isoelectric point were 51521.8u and 5.39 respectively. This protein was hydrophilic protein, and there was no transmembrane region. The analysis results laid a theoretical basis for construction of genetic engineering bacteria.