The present invention relates to utilization of an artificially synthesized nucleic acid, and more particularly, to a quantitative analysis method capable of quantitatively adjusting gene-based microbial community analysis results by preparing a microorganism 16S rDNA gene, which has a single nucleotide polymorphism (SNP) at a particular location so as to be differentiated from a gene of a target microorganism on the nucleotide sequence, and then using the microorganism 16S rDNA gene as an internal standard material which is quantifiable through nucleotide sequencing.