The full-length cDNA of GST was cloned in order to explore molecular response mechanism in broccoli under acid rain stress,which was analyzed by bioinformatics method and real-time PCR.The results showed that the full-length DNA was of 915 bp,opening reading frame(ORF) was of 642 bp.And the ORF encoded 213 amino acids,suggesting a formula of C₁₀₉₁H₁₇₁₉N₂₈₉O₃₀₆S₅,a molecular weight of 23 940.7,had no transmembrane helix region or signal peptide.Phylogenetic tree analysis revealed that this gene of broccoli had closer relationship with that from Brassica juncea.The analysis by real-time PCR suggested that the expression of GST genes in broccoli under acid rain stress increased significantly at first,and then declined due to longer duration of acid rain stress,which was involved in signaling pathways in response to the acid rain stress.