A novel design for an ethanol injection system has been proposed, which consists of one pump chamber, two valves, and one central-vibrating piezoelectric device. The system uses a microdiaphragm pump with a piezoelectric device for microdirect alcohol fuel cells. The diameters of the pump chamber are 31 mm and 23 mm, and the depths of the chamber are 1 mm and 2 mm. When the piezoelectric device actuates for changing pump chamber volume, the valves will be opened/closed, and the ethanol will be delivered into DAFC system due to the pressure variation. The chamber dimensions, vibrating frequencies of the piezoelectric device, and valve thickness are used as important parameters for the performance of the novel ethanol injection system. The experimental results show that the ethanol flow rate can reach 170 mL/min at a vibrating frequency of 75 Hz. In addition, the ethanol flow rate is higher than the water flow rate.