Genome-wide association study is an important approach to identify common genetic variants that predispose to human disease. Because of the high cost of genotyping on hundreds of thousands of markers on thousands of subjects, a more cost-effective two-stage case-control design is applied by most genome-wide association studies. To describe the design and statistical methods of the two-stage case-control study, this paper introduces the principles of two-stage case-control design, its implementing steps in genome-wide association study and the features of its application. The method is illustrated with an example.