In shellfish culturing and breeding practice, the width of shell growth lines is an important index to measure the growth rate of shellfish,and anal angle radial rib is the part with the widest growth lines. In order to explore the feasibility of taking anal angle radial rib length as a typical growth trait, this research analyzed the correlation between anal angle radial rib length （X₁） and other growth traits, such as shell length （X₂）, shell height （X₃）, total height （X₄）, shell width （X₅）, live body weight （Y₁）, soft tissue weight （Y₂） and shell weight （Y₃） of Hyriopsis cumingii at different ages and conducted the path analysis of body size traits to body weight traits （live body weight, soft tissue weight and shell weight）.The results of correlation analysis showed that there was a significant positive correlation between anal angle radial rib length and body weight in the first to third instars of H. cumingii. The correlation coefficient between shell length and live body weight was the highest in the first and second instars of mussel, while the correlation coefficient between anal angle radiating rib length and live body weight was the highest in the third instar of mussel. In addition, the correlation coefficient between anal angle radiating rib length and live body weight, soft tissue weight and shell weight showed an increasing trend with the increase of age. The data of path analysis and multiple regression analysis displayed that the main factors affecting the live body weight of 1 to 3 year old were anal angle radial rib length, shell length and shell width, the main factors affecting the soft tissue weight of 3 year old were shell length and shell width, the main factors affecting the shell quality of 1 and 2 year old mussel were shell length and shell width, and the main factors affecting the shell quality of the third instar mussel were anal angle radiating rib length, shell length and shell width. In conclusion, anal angle radial rib length, together with shell length and shell width, can be used as a new typical growth trait to represent the growth rate of H. cumingii.