Continuous positive airway pressure (CPAP) ventilator is an effective treatment device for obstructive sleep apnea syndrome (OSAS). A new control-module design for CPAP ventilator is discussed in this paper. The key technologies, which have improved the performance and reliability of the equipment, such as AVR-based module control, high-precision air pressure detection, improved digital PID control algorithm and smart motor-drive regulation, are described. As indicated by the results from our experiments, the proposed design promises a stable output pressure of the ventilator, the error being less than 0.5cmH(2)O.