Based on dSPACE real-time simulation system and LabVIEW measuring system, semi-physical simulation platform of DC motor speed-adjusting system was established. Fuzzy PID algorithm was designed based on analyzing fuzzy control and PID control for speed-adjusting system. The simulation results show that compared to standard PID algorithm, fuzzy PID algorithm improves the performance of speed-adjusting system for DC motor. On this basis, the speed-adjusting system was developed based on ATmega128 single-chip and original algorithm. Compared with simulation speed-adjusting system, there is no obvious difference on response characteristics.