Abstract: Recently, as microfluidic devices have been widely used in the chemistry, life science, lab-on-a-chip, micro electro mechanical systems(MEMS) and so on, the characterization of fluid behavior at the scales of micro and nanometer levels is essential. Because of the small scales and low Reynolds numbers, surface forces become important relatively. The flow behavior in micro-scale is significantly different from that in macro-scale and many complex phenomena are not clear. Micro-scale particle image velocimetry is a kind of full field, instantaneous and quantitative method that can be used to characterize the performance of such microfluidic system with spatial resolutions better than one micron. It has been an important measurement technique and been widely studied. In this article, the recent development of Micro-PIV including the fundamentals the technique and the theoretical background is reviewed. An overview of the most relevant applications is given on the topics of near-wall flow, electrokinetic flow, mixing, biological application, bubble flow and so on, and its progress is forecasted.

Key words: Boundary slip, Flow visualization, Fluorescent particle, Microfluidic, Micro-scale particle image velocimetry (Micro-PIV)