This paper deals with the problem of robust control for continuous bioprocesses. According to the material balance equations of continuous bioprocesses, a uniform framework for mathematical modeling of this class of processes is first presented. Then a robust controller is designed by using the H?? mixed sensitivity method for the bioprocesses. Finally, the proposed H?? control strategy is applied to bio-dissimilation process of glycerol to 1, 3-propanediol. Simulation results are given which show that the designed robust controller ensures the system has a favourable robust tracking performance.