eDNA-metabarcoding is an efficient method in detecting biodiversity of marine benthic organisms based on the next-generation sequencing technology. However, public databases are currently not all-inclusive, which usually prevents accurate annotation to species, genus or even family levels for a majority of obtained OTUs. Here we want to introduce a possibility to accurately annotating the eDNA metabarcoding data obtained from sediments of coastal Chinese waters with a local DNA barcoding database of annelid polychaetes built based on samples collected from the China Seas. Besides, we also want to show some other extensive applications of local specimen/DNA barcoding library, such as in biodiversity, taxonomy, and biological resource conservation.