Abstract: A dynamic model for a transducer-electromotor-pressure loop and a fresh air valve-CO2 volume content loop was established in order to eliminate the coupling of each loop in a variable-air- volume (VAV) air-conditioning system and effectively control the system. In addition, decoupling control technology based on the PID (proportion-integral-differential) ANN (artificial neural network) was used to eliminate the coupling between the two loops. Its operation condition shows that the decoupling control technology based on the PID ANN is feasible to the decoupling control of the two loops in a VAV air-conditioning system.