To identify the intestinal roundworms of Eclectus roratus and Psittacula alexandri from the Guangdong region by morphological analysis and molecular biology techniques,and to amplify the mitochondrial genome of parrot roundworms using PCR,as well as to carry out phylogenetic analyses based on the sequences of their mitochondrial genes.The results showed that the parrot roundworms identified in this identification belongs to Ascaridia.nymphii and its mitochondrial genome consists of 12 protein coding genes,22 tRNA genes,2 ribosomal RNA genes and two non-coding regions.Phylogenetic analyses showed that A.nymphii identified in this study is located in the same evolutionary branch as the previously reported Ascaridia sp.,is closely related and con-stitutes a separate clade of avian ascarids with pigeon roundworms and chicken roundworms.This study provides important data for the classification,molecular epidemiology and population genetic evolution of parrot roundworms.