The digital control technology of a bearingless permanent magnet synchronous motor (BPMSM) includes torque control technology and radial suspension force control technology. On the basis of explaining the producing principle of radial suspension forces, electromagnetic torque equation and radial suspension force equations of the BPMSM are given. Based on the functional block diagram of the BPMSM control system, optimized software structure of the control system is designed, realizing methods of its various functional blocks and management mechanisms of two kinds of critical resources in TMS320LF2407A DSP are put forward. The experiment results show that, adopting this software structure and the realizing methods and management mechanisms, the functions of the BPMSM torque control, suspension control and human-computer interaction can be implemented well. The software structure and realizing methods and management mechanisms have important reference value for developing digital control of bearingless motors.