Abstract: Objective: To explore the preparation of the core-shell beads by using co-extrusion and to enhance oxidative stability of the encapsulated fish oil.Methods: For this purpose, evaluating the effect of different processing parameters such as different flow rates for fish oil, vibrational frequencies, drying methods and shell formulations on the characteristics of the coreshell beads.The microencapsulation efficiency, sphericity factor, the damage extent of dried beads, the appearance of beads, the peroxide value of fish oil ( POV) were investigated. The result showed that the optimum process conditions were as follows: the ratio of Alg to HMP solution was 3∶ 1 ( v/v) , core flow rate was 1.0 m L/min, vibrational frequency was 280 Hz and dried by freeze drying.The sphericity factor was 0.048, microencapsulation efficiency was 77.74%, water activity was 0.281. the POV of the emulsified fish oil was twice than the encapsulated fish oil, so that the beads had enhanced the oxidative stability of fish oil at these conditions.Conclusion: It was demonstrated that production of core-shell fish oil beads by co-extrusion was possible and that the process was stable and reproducible.