Abstract: Mitochondrial cytochrome b sequences (432 bp) were sequenced in 33 individuals of Oxya intricata from 9 different parts of China, homologous sequences compared, nucleotide composition calculated and the molecular phylogenetic tree was constructed with the Neighbor-Joining method using Gesonula punctifrons and Pseudomorphacris hollisi as outgroup species. In the sequences obtained, A%+T% was about 70.3% and 30 nucleotide sites were substituted (about 6.9%), among which only 5 substitutions resulted in the variation of amino acids. In the case of every amino acid code, A%+T% in the third site was much higher than the other two sites, reaching about 90.4%. The NJ tree suggests that different individuals from the 9 areas in China were distributed in different clusters, but no clear relationships between haplotypes and geographic regions could be inferred. Since the branches of clusters are parallel, there is no evident difference between different areas.

Key words: Oxya intricata, mtDNA, cytochrome b gene, genetic relationship