A Setosphaeria turcica gene encoding the catalytic subunit of calcineurin was cloned using degenerated primers corresponding to conserved domains of Ser/Thr protein phosphatases and its complete cDNA (GenBank accession No. EF 407562) was obtained with RACE method. It's validated single copied model by southern hybridization. Furthermore, the CNA inhibitor Cyclosporin A (CsA) exhibited potent antifungal activity against conidial germination and appressorium formation of S. turcica. The inhibition ratio was positively correlated to CsA concentration. However, appressorium formation was more sensitive than conidium germination to the inhibitor at the same concentration. It was suggested that CNA might play an important role in the pathogenicity of S. turcica.