Abstract: The present invention relates to a method for determining the DNA quality of a biological sample and, more specifically, to a method for determining the DNA quality of a biological sample by performing a quantitative polymerase chain reaction (PCR) using primers capable of amplifying a target gene, a method for preparing the primers used in the method, and a method for standardizing the amount of detected target gene mutation by using the determined DNA quality. The method of the present invention enables objective evaluation of the DNA quality of a biological sample used in gene analysis and the presentation of objective results on the expression ratio of a gene mutation, thereby providing reliable information in the fields of clinical research and companion diagnosis.