Abstract: There are more than 1 500 species of Platypodid beetles （Coleoptera：Platypodidae） known around the world. The taxonomy of this group is disputable. The phylogenetic relationships of Platypodid beetles is explored based on molecular gene information in this study. The mtDNA COⅠgene sequences （549 bp） of ten Platypodid species ［Euplatypus parallelus （Fabricius）, Euplatypus hintzi Schaufuss, Euplatypus solutus Schedl, Dinoplatypus cupulatus Chapuis, Dinoplatypus cupulatulus Schedl, Dinoplatypus calamus Blandford, Diapus quinquespinatus Chapuis, Treptoplatypus solidus Walk, Platypus quercivorus Murayama and Platypus lewisi Blandford ］ were sequenced. Software MEGA3.1 was used to analyze the sequence composition and genetic distances. Three molecular phylogenetic trees of Platypodidae were reconstructed using PAUP4.0 according to distance/neighbor-joining, maximum parsimony and maximum likelihood methods. The molecular results were compared with the morphological taxonomy. Furthermore, the phylogenetic relationship among the species and genera to which each species belongs was discussed. The results show that the genetic distances between Platypodid species and the outgroup Orthotomicus erosus Wollaston of Scolytidae （0.288-0.338） are higher than those within Platypodid species （0-0.226）. Genus Diapus is diverged the earliest from the phylogeny tree, and then the genus Euplatypus. Genera Treptohlatypus, Dinoplatypus and Platypus are closely related and diverged last. The result of molecular phylogeny of the Platypodidae is basically the same as that based on morphology revised by Wood （1993）. This indicates that the taxonomy system of Platypodidae has become more reasonable.

Key words: Platypodidae, mtDNA, COⅠ, phylogeny, genetic distance, divergence