Dimorphopterus japonicus is a kind of pest which seriously harms sorghum and millet. In this study, we sequenced the mitochondrial whole genome of D. japonicus (Hidaka, 1959), and characterized and analyzed the mitogenome. The D. japonicus genome length is 15,473 bp, and it exhibits a typical high A + T content (77.6%). The mitogenomic structure of D. japonicus is highly conservative and there are no gene rearrangements. The evolutionary rates of the PCGs are in the order of atp8 > nad3 > nad6 > nad2 > nad5 > atp6 > nad4 > nad4L > cox2 > nad1 > cytb > cox3 > cox1. By using the Bayesian inference and maximum likelihood methods, we inferred the phylogenetic relationships within Lygaeoidea and estimated their divergence times based on concatenated mitogenome genes. The stable clades of (Oxycarenidae + Piesmatidae), (Malcidae + Colobathristidae), (Meschiidae + Berytidae), and (Blissidae+(Cymidae + Ninidae)) were consistently recovered in all analyses. Estimated divergence times revealed that the divergence time of the Lygaeoidea was 99.4 Ma (95% HPD: 83.4-124.8 Ma), and most lygaeoid families diverged during the early Cretaceous to late Paleogene. Berytidae is the latest differentiation in the lygaeoid families, and the genus Dimorphopterus was differentiated in 45.9 Ma (95% HPD: 39.8–47.7 Ma). This study is of great significance for reconstructing the phylogeny of Lygaeoidea and providing insights into its evolutionary history.