The full length sequence was cloned from the leaves of brassica napus according to the EST of RNA-Seq through RT-PCR and rapid amplification of cDNA ends(RACE) techniques which had been deposited in GenBank database with the accession number of KF740477. The full length of BnCDPK1 amplified from cDNA is 2115 bp, compared to 2857 bp from gDNA which include 11 introns and 12 exons. Bioinformatics analysis showed that BnCDPK1 contain an entire opening reading frame of 1581bp, which encode a polypeptide of 527 amino acid residues possessing a serine/Threonine protein kinase catalytic domain(S_TKc ) and four EF-hand calcium-binding domains, and it shared high identity with AtCPK28 and belong to the CDPKs subgroup Ⅳ. Fluorescent quantitative PCR analysis displayed it was constitutively expressed in all tested organs, but the transcript abundance was relatively higher in leaves and stems , then in roots and seeds, and less was in flowers. It can be induced by Sclerotinia sclerotiorum infection in both high resistant and susceptible cultivars, however, the relative transcript level was higher in the former in all time periods , 1.4 fold before inoculation, 4 fold for12hpi and 3 fold for 24hpi.Thus it was deduced to involve in growth and development in oil seeds, and play an important role in the defense reaction to Sclerotinia sclerotiorum.