In the present study, attapulgite pellets with a diameter of 2 mm were selected as inorganic carriers, and the native microorganisms screened from culture pond were immobilized using the adsorption method to create immobilized microbial pellets. The characteristics and performance of these pellets on removal of COD_Mn and ammonia from aquaculture wastewater were investigated. The results indicate that immobilized microbial pellets have good mechanical strength. The number of bacteria released into water can be maintained at 1.5×10⁶ CFU/mL, and the sustained release performance can be maintained under different environmental conditions. The immobilized microbial pellets can efficiently degrade COD_Mn and ammonia, and the degradation kinetics fit the Monod model very well. The effect of environmental conditions on the degradation performance of immobilized microbial pellets showed that neutral conditions are suitable for the degradation of COD_Mn, while neutral and alkaline conditions for ammonia. There is no significant difference in the degradation of COD_Mn with different gas flow rates (P>0.05). The higher the dissolved oxygen in the water is[DO=(8.600±0.028) mg/L], the higher the ammonia removal rate is. As the initial concentration of pollutants increase, the first-order rate constants of COD_Mn and ammonia gradually increase (except the too high ammonia concentration). Within 10~35℃, the higher the temperature is, the first-order rate constants of COD_Mn and ammonia is.