With the unique geography and complex environment, the Northwest Pacific Ocean has nurtured extremely rich fishery resources, becoming a hotspot for global marine biodiversity conservation and fishery management. In order to more effectively identify and investigate the diversity of fish species, a local DNA barcodes database of common fish in Northwest Pacific Ocean was established. Based on the COⅠ gene sequences of fish, 307 samples of common fish were collected in Northwest Pacific Ocean from June to August 2023. These common fish belonged to 20 genera, 13 families, 7 orders, and 25 fish species. 77. 96% of COⅠ sequences can be compared to high similarity sequences in public database. The average interspecific genetic distance was 0. 233, and the average intraspecific genetic distance was 0. 003, and the interspecific genetic distance was 77. 67 times that of the intraspecific genetic distance, and it could form obvious bar code gap. The phylogenetic tree based on COⅠ gene sequences showed that fishes of the same genus first clustered into a single branch, then with fishes of the same family, and finally with fish of different families of the same order. In summary, the COⅠ gene has species specificity and can effectively distinguish common fish species in the Northwest Pacific Ocean. The initial establishment of the DNA barcode database of common fish is conducive to the monitoring and investigation of fish diversity in Northwest Pacific Ocean using environmental DNA technology, providing technical support for biodiversity conservation, resource management, and population dynamic monitoring in Northwest Pacific Ocean.