Abstract: 【Objective】 This study aimed to investigate and elucidate the relationships between morphological traits and body masses of male and female Hippocampus trimaculatus brood stocks using correlation and path analyses， thereby providing a theoretical basis for breeding of male and female Hippocampus trimaculatus brood stocks.【Method】 Body mass as well as 13 morphological traits （head length， snout length， eye diameter， head height， coronet length， pectoral fin width， trunk width， trunk length， body height， dorsal fin base width， caudal peduncle width， tail length， and body length） were measured in Hippocampus trimaculatus brood stocks. Descriptive statistical analysis， correlation analysis among traits， path analysis of morphological traits on body mass， and determination coefficient analysis were performed. With body mass as dependent variable， key morphological trait as independent variable， multiple regression equations were established and single-factor curve fitting analysis was performed.【Result】 The coefficient of variation for body mass in both male and female brood stocks was higher than that of all other morphological traits. In male brood stocks， all morphological traits showed extremely significant positive correlations with body mass （P<0.01， the same below） except coronet length （P>0.05， the same below）. In female brood stocks， all morphological traits showed extremely significant positive correlations with body mass， except coronet length. In male brood stocks， body length and body height exerted significant positive direct effects on body mass （P<0.05， the same below）， and total length showed slightly greater direct effects. In female brood stocks， body height， snout length， and eye diameter had significant positive direct effects on body mass， and snout length had the strongest direct effects.【Conclusion】 Body length and body height are the main morphological traits influencing body mass in male Hippocampus trimaculatus brood stocks； body height， snout length， and eye diameter are the main morphological traits influencing body mass in female Hippocampus trimaculatus brood stocks. Body length has the greatest direct effect on body mass in male brood stocks， while snout length has the greatest direct effect on body mass in female brood stocks. For artificial breeding of Hippocampus trimaculatus， body length and body height should be the main selective indexes for males， whereas snout length and body height should be core selection indexes for females.