Abstract: Microstructure and characteristics of potato granule powder and flake powder were investigated by optical microscope,Brabender viscometer,SEM,XRD,FT- IR respectively. The results showed potato granule powders exhibited mainly oval or irregular shape with different size distribution,featured by structural integrity,surface cracks,weaker water adsorption,high content of protein and reducing sugar. Granule powders owned lower apparent viscosity,around 20 BU,and Brabender viscosity curves were overall displayed straight.Comparatively,flake powders were viewed flat,polygon shape with rough surface,irregular edge and cracks.Disappear diffraction peaks of XRD patterns showed typical of amorphous structure.Flake powders owned higher viscosity,apparently changed viscosity curves,free pregelatinized starch dispersing in the solution.