The present work presents the availability of using porous matrix in microfluidic devices as a solid phase matrix for immunoassays. Porous matrixes on the surface of the microchannels were microfabricated by MEMS technology and electrochemical etching technology, which were coated on the wall of the rectangular microchannel in the microdevices to provide a surface-enlarging matrix. The microfabrication process of porous matrixes was investigated and optimized. Then the surface morphology of the porous matrixes was characterized by SEM. Both direct method and dual-antibody sandwich method were used for fluorescence immunoassays. Using sandwich immunoassay, 6.25μg/mL - 25μg/mL human IgG in real samples have been detected with a correlation coefficient of 0.9773. These porous microdevices have shown some advantages over its large-scale counterparts, including lower sample and reagent consumption, lower cost, less analytical time and so on, which enables detection for clinical testing.