In order to research the relationship between the morphological traits and body mass of Hexagrammos otakii, 150 tails of six-month and eighteen-month Hexagrammos otakii were randomly sampled for measuring body,mass and eight morphological traits including full length, body length, body height, body width, head length, trunk length, length of tail stalk, height of tail stalk, and correlation analysis, regression analysis and path analysis were used to study the eight morphological traits on the impact of the body mass.A significant positive correlation between morphological traits and body mass of six and eighteen months of Hexagrammos otakii were observed,with extreme significance(P<0.01),and the main morphological traits of body mass affected by different age of month were different. Six-month and eighteen-month Hexagrammos otakii were selected for the four morphological traits of body length, head length, body height, body width and full length, body height, height of tail stalk and body width by gradual introduction and gradual elimination method and the multiple regression equations were established:Y=-13.54+1.905X₂+1.222X₃+1.211X₄+1.499X₅, Y=-173.415+8.85X₁+11.18X₃+9.65X₄+20.749X₈. The results of path analysis showed that the morphological traits with the greatest direct effect on body mass of the 6-month-old and 18-month-old greenling were body length (0.706) and full length (0.538), respectively, and body length, head length, full length and body height had a decisive effect on the body mass of greenling at 6 months and 18 months.In addition to the morphological traits of the above, it should be combined with body width for breeding. The results of the study could provide important reference for the use of the morphological traits of Hexagrammos otakii for breeding.