Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), as a conventional molecular technique, was utilized to analyze the diversity of oral microbiota. However, studies found that the results of PCR-DGGE were affected by the DNA isolation method. This study compared QIAamp DNA Micro Kit extraction method with the phenol and chloroform extraction method for DNA isolation of saliva of healthy youths and analyzed PCR-DGGE fingerprints.