Abstract: Rubisco activase (RCA) is a chaperone that promote and maintain the catalytic activity of Rubisco,which is the critical enzyme in plant photosynthesis.To clarify the role of RCA gene in Brassica oleracea,which homologous with the BnRCA gene encoding Rubisco activase of Brassica napus,was cloned from Brassica oleracea.The full length of the BoRCA gene was 1388 bp and contained a 1317 bp open reading frame (ORF) encoding a 438 amino acid precursor protein.The BoRCA shared 99.57% and 99.77% identity, respectively, with that of BnRCA at the nucleotide and amino acid level.The BoRCA contained a predicted N-terminal transit peptide to chloroplast stroma, two high conserved ATP-binding domains and multiple phosphorylation sites.Multiple sequence alignment and phylogenetic tree revealed that BoRCA belongs to β isoform of RCA protein and has high identities with other plant RCAs.The results of semi-quantitative RT-PCR showed that the expression of BoRCA was the strongest in mature leaves, but no in roots and old leaves,and the expression under low temperature was significantly lower than room temperature.These results lay a foundation of further study on the photosynthesis mechanism of RCA in Brassica oleracea.