In this paper, a nonlinear dynamical system is proposed to describe glycerol bioconversion to 1,3-propanediol (1,3-PD) in continuous fermentation process. Some important properties of the system are then discussed. To maximize the concentration of 1,3-PD at the steady-state moment, an optimization model by taking the concentration of glycerol in the feed flow and the dilution rate as optimization variables is presented. Finally, an improved Particle Swarm Optimization (PSO) algorithm is developed to seek the optimal solution. Numerical results show that the concentration of 1,3-PD at the steady-state moment is increased considerably.