1,3-propanediol fermentation by immobilized Klebsiella pneumonia was studied.The calcium alginate was found that it has great advantages in the microcapsules preparation and 1,3-propanediol productivity by the comparison study of four kinds of common embedding materials.The optimum conditions of calcium alginate encapsulation were sodium alginate of 6%(w/v),calcium chloride of 4%(w/v),crosslinking time of 4 h.The concentration of 1,3-propanediol in the broth increased by 7.4% compared with free fermentation,and the productivity of 1,3-propanediol reached 1.04 g/(L·h).Moreover,the immobilized Klebsiella pneumoniae can be used for semi continuous 1,3-propanediol fermentation.