| Objective In order to finely regulate the order of medicine market and to promote the standardization and scientific development of the industry. Methods Different growth ages of Hippocampus kuda (1770 individuals) were collected and determined their shape, color, hardness, and odor. These data were classified by multivariate statistical analysis, and then the seahorses were rated rating by chemical composition. Combined with production practice, a grading model for commodity specifications were developed in this study. Results The results of statistical analysis indicated that the 10 indicators, such as body weight, body length, ratio of trunk length and body width, ratio of head length and snout length, ratio of body length and head length, colors of L?, b?, smells of R2, R5, R9, active ingredients of polar amino acids, glycoproteins, sterols, as the grading indexes. The seahorse was divided into four groups and eight groups by correlation analysis, principal component analysis, cluster analysis and gray relational analysis, and their rationality was verified by fisher discriminant analysis. Conclusion It showed that body weight and body length could be used as the primary indicators of rating, which was consistent with the traditional empirical evaluation. However, the discriminant model established in this paper was more comprehensive and the accuracy rate was as high as 96.3%. This study has certain practical significance and reference value.