Through the monthly measurement on the shell length, shell width, total weight, weight of body mass, shell weight and weight of pearls of the freshwater pearl mussel Hyriopsis cumingii from May to November，the growth pattern of the 2 year old pearl mussel in its main growing season and its correlation with the growth of the pearls were studied. Results showed: the relation between the pearl weight (PW) and the shell length (SL) and shell weight (SW) were PW=0.0008SL^3.3946 (R²=0.6948) and PW=0.7809SW^1.0227 (R²=0.6888), respectively, while the relation between PW and total weight (TW) of the mussel, weight of body mass (BW) and weight of the shell (W) were PW=0.0021TW^1.5434 (R²=0.7337)，PW=0.107BW^0.9125 (R²=0.7158) and PW=0.0324W^1.1259 (R²=0.7101), respectively. The relationship between TW and SL, SW were exponential curve fitting and could be expressed as TW=16.003e^0.1681SL，(R²=0.7961) and TW=64.311e^0.1372SW (R²=0.6822), respectively, while the relation between BW and SL, SW, and the relation between W and SL, SW were all power function fitting, and could be described as BW=0.0188SL^3.1427，(R²=0.6927), BW=12.446SW^0.8974 (R²=0.617), W=0.0656SL^2.7721, (R²=0.8271) and W=19.876SW^0.802 (R²=0.7563), respectively. Results of this study indicated that there exist a significant correlation between the pearl growth and the growth of the mussel, which suggested that to learn the growth of pearls, it is no more necessary to direct measure the pearls by dissecting sample mussels, instead, it is now possible to measure the weight and shell length etc. of the mussels and the growth of the pearls could be also well learnt through the correlation obtained.