Abstract: Experiments on friction factor and heat transfer performances were conducted in micro-channels with deionized water as working fluid.It was found that the friction factor and heat transfer characteristics in micro-channels deviated from theoretical predictions for conventional channels.The measured fRe values was higher than classical theory prediction and increased with increasing Reynolds number, while heat transfer coefficient was lower than the prediction.The influence of surface roughness of channel wall,which was the possible reason for the deviation was discussed.It was also found that for the same thermal resistance, higher inlet temperature and heat flux were able to decrease pressure drop.The friction correlation for the lamina flow,was proposed on the basis of experimental data.