Fed-batch fermentation is a conventional process for fermentative production of 1,3-propanediol,but the productivity is relatively low.By contrast,continuous fermentation can obtain a relatively high productivity since dynamic equilibrium is achieved and 1,3-propanediol can be produced steadily at a high rate.In this work,fermentative production of 1,3-propanediol with Klebsiella pneumoniae by several continuous fermentation processes was studied,and the operational dilution rates were optimized in order to get a high product concentration.The experimental results of single and multiple-stage continuous fermentations with different dilution rates were also compared.It was found that two-stage continuous fermentation was an favorable process for 1,3-PDO production with 1,3-PDO concentration of 68.11 g/L and productivity of 1.89 g/(L·h) at an overall dilution rate of 0.028 h-1.Compared with 48-hour fed-batch fermentation,the productivity was increased by 27.7%.