DNA is made up of molecules called nucleotides. There are four different nucleotides in DNA which are called Adenine, Guanine, Cytosine, and Thymine, or simply A, G, C and T. Determining the order of these bases is called DNA sequencing. This sequence determines the genes and these genes specify an individual’s unique traits. Therefore, the genetic research plays an important role in detection, prevention and treatment of diseases which are caused by genetic abnormalities and mutations. Common DNA sequencing methods are usually based on chemical reactions. These methods have some disadvantages for example they are expensive and also they cause losing DNA. So, in recent years the progress in molecular scale simulation methods has made various approaches for DNA sequencing. In this paper, a suitable method for DNA sequencing has been presented and its accuracy is investigated by molecular dynamics simulations. In this method, DNA molecule passes through the carbon nanotube first, and then the graphene nanopore, with a specific speed. Different bases are determined by analyzing the required force for passing DNA. In this proposed method, the speed and cost of sequencing are improved.