Fabrication of a self-packaged partial semicircular nanoporous microchannel is demonstrated using electrospinning, self-limiting ultraviolet lithography, and thermal-reflow packaging processes with SU-8. The fabrication process offers unique advantages of microresolution channel patterning, alignment free seamless integration of nanofibers in a microchannel by self-packaged reflow, and easy formation of 3-D nanoporous channels. A fabricated nanoporous microchannel with a channel length of 7 mm, a channel width of 73.85 mu m, and a channel height of 34.65 mu m shows slow fluidic flow through the channel, functioning as an effective nanochannel with an equivalent channel height of 800 nm and a radius of 857 nm, and therefore, its reduction ratios of the channel height and radius are similar to 97.7% and 97.8%, respectively.