Mitochondrial genome is a circular double-stranded DNA.  Mitochondrial DNA (mtDNA) is replicated by the specific enzymes into the mitochondria and independent of nucleus.  A cell contains thousands of copies of double-stranded DNA in the inner mitochondrial matrix.  In the first stage of DNA replication requires a small RNA that has been produced with the mitochondrial RNA polymerase and can provide the necessary primers for DNA mitochondrial replication.  Several methods have been proposed for replication such as an asynchronous strand displacement model, a strand-coupled bidirectional replication model and RITOLS model.  This review paper is consider more models today as of mitochondrial DNA replication and proteins involved in replication of mitochondrial such as human DNA polymerase and the following of its subunites, DNA helicase mitochondria  or Twinkle helicase, proteins bonded to the single-stranded DNA  and  base excision repair in mitochondria.