The contamination of heavy metals by mining and combustion of fossil fuel has brought about significant deleterious consequences not only to environment but also to human health. Ramie(Boehmeria nivea L.) is a China originated fiber crop that has great ability to tolerate and accumulate heavy metals. To explore the mechanism of ramie to tolerate cadmium, we isolated and analysed a novel gene(BnPCS1) exhibiting high homology with phytochelatin synthase gene(PCS) from Zhongzhu 1 ramie by RT-PCR and RACE methods. The full length sequence and the ORF of BnPCS1 gene is 1 888 bp and 1 512 bp, respectively, which encodes 503 amino acids(56.02 kDa) with a pI value of 6.76. The similarity comparison revealed that the deduced amino acid sequence shares 74%, 73%, 75%, 73% and 77% of homology with Lotus japonicas(Q2TSC7), Nelumbo nucifera(BAN08523), Pyrus betulifolia(AEY68568), Sesbania rostrata(ACT87974) and Sophora viciifolia(AFM38979). Real-time quantitative PCR was used to analyze expression pattern of BnPCS1 in different organs and under Cd, ABA and SA treatment. We found that BnPCS1 was mainly expressed in mature leaf and highly induced in leaf by Cd and ABA treatment, respectively. These results indicated that BnPCS1 may be involved in response of ramie plants to Cd stress. In this study, we succeeded cloned an phytochelatin synthase gene(BnPCS1) and studied in primary level, which established the foundation for the future study in the mechanism of ramie to heavy metal Cd stress.