Based on the RNAseq data of Pb²⁺induced tartary buckwheat leaves, we cloned a phytochelatin synthase gene (FtPCS) from Fagopyrum tataricum using the RTPCR method. The FtPCS gene was subcloned into pET28a(+) using Infusion technology, which was expressed in Escherichia coli BL21 Star(DE3). Being applied with Pb²⁺, the catalytic activity of the purified FtPCS protein was detected by reverseHPLC involving DTNB (5,5′dithiobis2nitrobenzoic acid) postcolumn derivatization method. The results indicated that the full length of genomic sequence of FtPCS was 5 456 bp, containing 8 exons and 7 introns; the CDs sequence of FtPCS was 1 485 bp in length, which encoded a 55.10 kDa protein consisted of 494 amino acids. The FtPCS was highly expressed in E.coli in the form of inclusion body, which was refolded by dialysis and purified by Co²⁺ chelation chromatography. The purified FtPCS recombinant proteins still kept the biological activity for transforming GSH to PC compounds, and the low concentration of Pb²⁺ could remarkably increase its catalytic activity.