There are many reports on the study of microencapsulated bifidobacteria, the effect of concentration of sodium alginate, emulsifying time and immobilized time on microcapsulation of B. bifidum BB28 and BB01 have been invesgated. This study reported the viable counts and encapsulation yield (EY) of B. bifidum BB01 and BB28 encapsulated in different cell suspension-alginate ratios (1:5, 1:10, 1:15 and 1:20), in different Tween 80 content(0.2%, 0.4%, 0.6% and 0.8%) and in different oil-water ratios (1:4, 1:5, 1:6 and 1:7). It was studied by single factor experiment method, the results showed that this several factors impacted the viable counts and encapsulation yield (EY) of B. bifidum BB01and BB28 significantly, and the optimum cell suspension-alginate ratios for B. bifidum BB01 and BB28 were 1:5 and 1:10 respectively; the optimum Tween 80 concentration for B. bifidum BB01 and BB28 were 0.8% and 0.6% respectively; the optimum oil-water ratios were 1:6 and 1:4 respectively.