For reviewing Korean species of Denticollinae and reconstructing phylogenetic relationships between subfamilies in Elateridae, three kinds of studies were conducted: 1) taxonomic review based on morphology; 2) DNA barcode for Denticollinae; 3) molecular phylogenetic study of Elateridae using 12 genetic markers. In taxonomic study, a total of 54 species were reviewed including 13 new species and then unrecorded species. In DNA barcoding, six cryptic and/or pseudocryptic species were confirmed by their sympatric or allopatric distribution. We propose a conservative threshold of 3.6% for convenient molecular operational taxonomic unit identification in Denticollinae. From this study, we confirmed that COI sequence is useful for reassessing species diversity for polymorphic and polytypic species occurring in sympatric and allopatric distributions. In molecular phylogenetic study, the phylogenetic inference constructed robust phylogeny with almost very strongly supported nodal values(>90%) and showed that Hypnoidinae, Oxynopterinae and Denticollinae are monophyletic; Elaterinae, Hemiopinae and Melanotinae are a monophyletic group; and two tribes in Denticollinae are paraphyletic, it is needed to reclassify their systematic accounts.