Abstract: Based on the producing 1,3-propanediol from continuous fermentation of glycerol, a dynamic system model and its parameter identification were investigated. Firstly, under substrate-excess conditions, according to the dynamic behaviors and characteristics, the corresponding nonlinear dynamic system was improved by considering intracellular substances and 1,3-propanediol. Then the major properties of the system were discussed. Secondly, optimization model of parameter identification was proposed with average relative error as objective function, and it was solved by Particle Swarm Optimization algorithm. The results showed that the system fits for the dynamic behaviors of 1,3- propanediol but not for other by-products.