The particle size, dispersion, and stability of a microencapsulated diet developed for the pearl oyster, Pinc- tada martensii, were measured in this study. An experiment was conducted to evaluate pearl oyster feeding and diges- tion, in which the experimental group (EG) was fed a microencapsulated diet, and the control group (CG) was cultured at sea. Survival rate, growth rate, biochemical components in the dried edible part, and digestive enzyme activities were measured and compared in the two groups after 45 days. The results showed good dispersion of the diet, a particle size < 48 μm, and that of about 80% of the particles were 28–48 μm. The settling velocity in 35 NaCl solution was (2.74±0.21) mm/s under static conditions. The nitrogen retention rates of the diet soaked in 35 NaCl solution for 120 min at 25℃ and the diet soaked in 35 NaCl solution for 60 min at 35℃ were (79.10±0.15)% and (80.85±0.72)%, respec- tively. No significant difference in survival rate was observed between the EG and CG, whereas the absolute and rela- tive growth rates of shell length, shell width, shell height, and total weight in the EG were significantly lower than those in the CG (P<0.05). The lipid component of the edible part was significantly higher in the EG than that in the CG (P<0.05). No significant differences were observed in the carbohydrate, protein, or ash components of the edible part between the EG and CG. The hepatopancreas of pearl oysters in the EG was saffron-yellow. Amylase, protease, and cellulase activities of the hepatopancreas of pearl oysters in the EG were not significantly different from those in the CG. A significant difference was observed in amylase activity between the two groups (P<0.05). These results suggest that this microencapsulated diet had appropriate particle size and stability and was absorbed and digested by the pearl oyster. Further studies should be conducted to optimize diet composition and farming protocols, which will be helpful for de- veloping indoor pearl oyster farming.