Abstract: Comparing with the fluid flow driven by electric field, fluid flow driven by pressure gradient is with simplicity and flexibility for actual applications. However, in the fluid flow driven by pressure gradient, the fluidic characteristic of analytes becomes more complex. Hereby, in this study, basing on the analysis and study of the fluidic characteristic of analytes, as well as the fluidic features of two miscible fluids of similar properties along a narrow rectangular shape slit within a Y-shape microfluidic device, the convection and diffusion transport in a pressure driven creeping flow is investigated, in the meantime, a two-dimensional analytical model is proposed and its corresponding analytical solution is obtained resorting to the average analysis.

Key words: Microfluidic, Pressure-driven flow, Taylor-Aris dispersion, Transport