Fish body morphology contains important ecological information and is a valuable feature for species identification and population classification. There are many kinds of fish in Northwest Pacific Ocean, making the study of fish biodiversity a significant challenge in the study of fish morphology. At present, the study of fish species identification by using fish body geometric morphometrics is relatively lacking, and the classification effect of different fish body parts morphology is necessary to be discussed. In order to understand the morphological structural diversity of important fish species in Northwest Pacific Ocean, and effectively improve the efficiency of fish species identification in this area. In this study, the morphologies variation of 485 tails of 26 species from 24 genera, 14 families and 8 orders in Northwest Pacific Ocean were constructed based on landmarks data and geometric morphometrics, and the taxonomic effects of different body morphological parameters on species recognition were evaluated. The results showed that there were significant differences in fish body morphology among different orders and species. In addition, Multiple regression analysis （MRA） detected allometry in some species. In terms of classification, and the body and torso shape could be better distinguished from different species. Studies have shown that fish species in Northwest Pacific Ocean have a variety of body shape structures, and the heterogeneity of the life history of different species and genetic factors may be the reasons for the body diversity. This study can improve the fish taxonomy in Northwest Pacific Ocean and provide a scientific basis for the sustainable development and effective resource management of fish species in Northwest Pacific Ocean. Future studies can add more species and numbers in order to explore more universal morphological differences and taxonomic effects.