The effects of replacement of a dietary microalgae with a microencapsulated diet on gene expressionrelated to pearl production traits, growth and biomineralization were studied in the pearl oyster . Three experimental groups were set up: EG1 was fed the marine green alga ; EG2 was fed a mixed diet of the microcapsules and the algae; and EG3 was fed only the microcapsules. The expression level of the growth-related genes in the adductor muscle (A), and the biomineralization-related genes in the mantle central (MC) and mantle edge (ME), were detected and compared among the three treatments after a 170-day indoor farming period. The results showed that survival rate, retention rate, the pearl nacre thickness, and average mass of the harvested pearls did not significantly differ (EGFR, I in the A did not significantly differ among the three treatments (N19 in the MC did not significantly differ among the three treatments ( was higher in EG2 and EG3 than in EG1, and the expression level of <0.05). No significant differences were detected in the relative expression levels of in the ME among the three treatments ( was higher in EG2 and EG3 than in EG1 (<0.05). These results suggest that the microencapsulated diet can replace part of the microalgae diet, which may be helpfully applied in future studies of artificial feed development for pearl oyster .