Several physicochemical properties of potato powder were studied, including the material moisture, extrusion temperature and screw speed's influence. The results indicated that with the increase of material moisture, the water-solubility, iodine blue value of potato powder decreasing, water-absorption, oil-absorption increasing, expansibility increased firstly and then decreased, which was the largest in moisture of 35%, while the gelatinization temperature decreased firstly then increased, and the peak, valley, final viscosity, gelatin increasing gradually. Thermal stability was the strongest in the moisture of 30%. With the increasing of extrusion temperature, the water-solubility, iodine blue value increased gradually, water-absorption, oil-absorption decreasing, and the expansibility increased firstly then decreased, which was the largest in 170 ℃. Gelatinization temperature increased gradually, and the peak, valley, final viscosity, thermal stability and gelatin decreasing gradually. With the increasing of screw speed, the water-solubility, iodine blue value increased, but the water-absorption and oil-absorption decreased. Expansibility increasing firstly then decreasing, which was the largest at the speed of 360 r/min. Gelatinization temperature decreased gradually, but the peak, valley and final viscosity and gelatin increased, while, the thermal stability decreased firstly than increased, which was the lowest at the speed of 280 r/min.