Abstract: Using Pt-Ru/C and Pt/C as anode and cathode catalysts, the membrane electrode assembly was prepared and a single direct methanol fuel cell system was installed. The electrochemical performance of a direct methanol fuel cell (DMFC) at different technological parameters such as methanol flow, methanol concentration, methanol temperature and humidifying air temperature was investigated by means of steady-state galvanostatic and potentiostatic polarization. The experimental result shows that the output current density and power density were 68 mA·cm^-2 and 14.8 mW·cm^-2 respectively with ambient air as cathode oxidant when the working temperature was 25℃ and the output voltage was 0.22 V. The four technological parameters significantly affected the performance of a direct methanol fuel cell. In the experiment, the optimum technological parameters were the methanol flow of 2 mL·min^-1, the methanol concentration of 2 mol·L^-1, the methanol temperature of 30℃ and the humidifying air temperature of 40~60℃.