【Background】Anselmella miltoni Girault is a newly invasive phytophagous wasp in Taiwan, China, so far not detected on the Chinese mainland. The species is difficult to identify because this wasp is tiny and similar to other species of Hymenoptera. Studies on gene sequence with PCR may provide a useful identification tool. 【Method】Partial sequences of the mitochondrial 16S ribosomal RNA (rRNA) and cytochrome oxidase Ⅰ (COⅠ) genes in A.miltoniwere amplified and sequenced by using a polymerase chain reaction and DNA sequencing methods. A phylogenetic tree was built by using DNAMAN Maximum Likelihood method based on the COⅠ partial sequences. 【Result】Mitochondrial 16S rRNA and COⅠ PCR products were 426 bp and 488 bp in length, respectively. The sequence analysis results showed that A+T base composition in both 16S rRNA and COⅠgene sequences were higher than C+G. The phylogenetic tree indicated that the kinship between A.miltoniand Encarsia berleseiwere the most closely, the relationship between A.miltoni andChrysocharis nautilus, C.eurynotawere relatively distant. 【Conclusion and significance】This study identified a possible avenue for the molecular identification of A.miltoni.