Abstract: Provided is a diagnostic system for identifying target microorganisms and/or resistance genes in a sample, including a cell lysis unit, a target nucleic acid enriching unit, a sequencing unit, and a sequence analyzing unit, wherein the cell lysis unit is configured to lyse non-target cells in the sample, the target nucleic acid enriching unit equipped with an immobilized adsorption device is configured to deplete nucleic acids of the non-target cells and to enrich nucleic acids of the target microorganisms, and the sequencing unit and the sequence analyzing unit are configured to produce identification results of the microbial species and/or resistance genes from the sequences of the enriched nucleic acids. Also provided is a method for enriching target nucleic acids in a sample and a method for identifying target microorganisms and/or resistance genes by sequencing the enriched nucleic acids of the target microorganisms.