Abstract: Sequences of the Cyt b gene segments on mitochondrial DNA of 9 species of Apolygus China and Lygus Hahn (Heteroptera:Miridae:Mirinae:Mirini) were extracted by means of protease K digesting and sequenced to both directions.Nucleotide composition,nucleotide variation ratio between species as well as variation ratio of 144 amino acid coded by 11 segments of 433 bp of the 9 species from the two genera were calculated using phylogenetic analyzing software package Mega.Nucleotide variation ratio:less than 0.02 within Apolygus and less than 0.08 within Lygus (with the exception of a few species) but more than 0.10 between species of the two groups with the average variation of 0.15.Variation ratio of the amino acid:no difference among the species within Apolygus and Lygus themselves with only an exception of a difference of 13 amino acid between L.gemellatus and other species within Lygus,but there is stably a variation of 8 to 11 amino acids,I.e.a 5.6% to 7.6% variation between any species examined of Apolygus and that of Lygus.It is proved that there has been existed distinct difference between these two groups at molecular level and they separated very well,which strongly supports the taxonomic opinion that Apolygus is promoted to a generic taxon.