BACKGROUND: Probiotics have more functional effects and less survival  under hard acidic-bile circumstances of digestive system, and foodstuff products situation has persuaded investigators to find techniques to resolve this problem. Microencapsulation as a useful method has a perceptible effect in this regard. Objectives: The aim of this study was to assess the protective role of double coated beads of calcium alginate-chitosan-eudragit S100 achieved from microencapsulation of Lactobacillus acidophilus as a predominant flora of human and animals gut. Methods: Following activation of starter culture of L.acidophilus in MRS-broth medium,  centrifuge (at aspeed of 5000 rpm for 10 minutes) was used to purify bacteria. Extrusion technique was used for Microencapsulation of probiotic bacterium. The survey of beads solidity was carried out for 12 hours and the study of survival of microencapsulated bacteria was done for 120 minutes inside hydrochloric acid, phosphate buffer and digestive powder solution.  MRS-Salicin-agar and pour plate method and incubation at 37oC for 48 h was done for cultivation. Data were analyzed by means of an independent t-test. Results: Shape and size of beads were shown by optical microscope. The consequences demonstrated that survivability of microencapsulated bacteria in the mentioned conditions, in both situation with and without mechanical tensions, is significantly more than free bacteria (p<0/05). Conclusions: Microencapsulation with calcium alginate- chitosan-eudragit S100 plays a significant role  in increasing the rate of L. acidophilus viability.