In this study,we integrated a DNA barcoding project with an ecological survey on intertidal polychaete communities and investigated the utility of CO1 gene sequence as a DNA barcode for the classification of the intertidal polychaetes.Using 16S rDNA as a complementary marker and combining morphological and ecological characterization,some of dominant and common polychaete species from Chinese coasts were assessed for their taxonomic status.We obtained 22 haplotype gene sequences of 13 taxa,including 10 CO1 sequences and 12 16S rDNA sequences.Based on intra-and inter-specific distances,we built phylogenetic trees using the neighbor-joining method.Our study suggested that the mitochondrial CO1 gene was a valid DNA barcoding marker for species identification in polychaetes,but other genes,such as 16S rDNA,could be used as a complementary genetic marker.For more accurate species identification and effective testing of species hypothesis,DNA barcoding should be incorporated with morphological,ecological,biogeographical,and phylogenetic information.The application of DNA barcoding and molecular identification in the ecological survey on the intertidal polychaete communities demonstrated the feasibility of integrating DNA taxonomy and ecology.