Abstract: In this paper,we introduced principles and characteristics of the first,second and third generation of sequencing technology,then the applications of second sequencing technology were described.Because of complicated operation and high cost,the first generation DNA sequencing technology represented by Sanger sequencing method can not meet the needs of large-scale sequencing.The second generation DNA sequencing technology characterized by high-throughout and low cost including Solexa sequencing technology of Illumina,and Applied Biosystems SOLiD and Roche 454 now has been used in many fields of life science research.The third-generation sequencing technology which can sequence single DNA molecular has also been arisen,but not been widely used in life science research