The inner shell color of donor Hyriopsis cumingii, which affects the color of pearls obviously, has become an important trait for genetic improvement of pearl mussels. However, the inner shell color of the mussels is difficult to measure. The measurement difficulties decreased the efficiency of selective breeding. In this study, the 4-8 month-old mussels from purple and white strains were selected for evaluating the correlation between the inner shell color and the outer shell color of mussels. The results are as follows:In purple strain, at 6 months old, the maximum correlation coefficient in a^* between outer shell and inner shell, 0.537, appeared (P<0.01). At 5 months old, the maximum correlation coefficient in b^* between outer shell and inner shell, 0.724, appeared (P<0.01). For a^*, the maximum correlation coefficient between the outer shell of 5-month-old mussels and inner shell of 8-month-old mussels, 0.414, appeared (P<0.01). For b^*, the maximum correlation coefficient between the outer shell of 4-month-old mussels and inner shell of 8-month-old mussels, 0.327, appeared (P<0.01). In white strain, for a^* and b^*, the maximum correlation coefficients between the outer shell of 5-month-old mussels and inner shell of 8-month-old mussels, 0.424 (P<0.01) and 0.326 (P<0.05), appeared. In summary, 5-month-old is the best time to indirectly evaluate the inner shell color by measuring outer shell color in Hyriopsis cumingii. In this study, we revealed that there is correlation between outer shell color and inner shell color in juvenile Hyriopsis cumingii. The result is of great significance to instruct early selection on inner shell color in Hyriopsis cumingii.