To obtain phycocyanin with high optical activity, a PCB-ferredoxin oxidoreductase gene (pcyA) was cloned from the cyanobacterium Arthrospira platensis FACHB314 and constructed into the plasmid pET24a with the heme oxygenase 1 gene (ho1). The recombinant plasmid pET24a-ho1(314)-pcyA(314) was transformed into Escherichia coli BL21 with the plasmid pACYCDuet-cpcBA-cpcEF, which contained the genes of apophycocyanin (cpcA, cpcB) and chromophore lyase (cpcE, cpcF) from A. platensis FACHB314. The transformed strain showed specific phycocyanin fluorescence, indicating that the PcyA from A. platensis FACHB314 can effectively catalyze the synthesis of phycocyanobilin. And the fluorescence intensity was higher than that of the strain with the pcyA gene from the pattern cyanobacteria Synechocystis sp. PCC6803. Herein, the function of PcyA from A. platensis was verified, and this study provides a valuable resource for the genetic engineering synthesis of optically active phycocyanin. [ABSTRACT FROM AUTHOR]