Abstract: α order inverse system theory was used to accomplish decoupling control for a 5-dof magnetic bearing system. State equation of the magnetic bearing system was given. Linearization decoupling based on inverse theory for the system was done. Closed-loop controller of the system was designed based on ITAE criterion. Simulation and experiment results showed that there are no couplings among dimensions of freedom of the system after decoupling procedures. Comparing with PID controller, the decoupling controller has better dynamic and static performance.