Nanofluid minimum quantity lubrication (MQL) technique has recently attained a significant attention for mechanical machining processes to reduce environmental loads caused by full usage of metal working fluids (MWF). Nanofluid refers to a fluid containing nanoparticles, which has superior lubrication and cooling characteristics. This paper investigates the characteristics of a nanofluid MQL micro-grinding process through a series of experiments. The miniaturized desktop machine tool system is developed, and a small grinding wheel is used to effectively realize the nanofluid MQL micro-grinding process. Nanodiamond and nano-$Al_2O_3$ particles are selected, and the base fluid is paraffin oil. The experimental results show that nanofluid MQL is effective for reducing grinding forces and enhancing surface quality. In addition, it is demonstrated that the type, size and volumetric concentration of nanoparticles are critical parameters to have influence on the performances of micro-grinding process.