AlSb polycrystalline thin films were prepared by magnetron sputtering with an improved geometric target, and their structural, electrical and optical properties were studied. The results of XRD measurements suggest that the annealed AlSb thin films are Zinc-blende structure with the average size of about 23~31 nm, and the higher temperature promotes the crystallization of the films. The morphology obtained from the AFM measurements reveals that the surfaces of the films are smooth and the particles are uniform with the average size of about 50 nm. Hall Effect measurements show that AlSb films are p-type semiconductors and the test of temperature dependence of dark conductivity in vacuum indicates the conductivity activation energys are 0.05 eV at low temperature and 0.13 eV at a higher temperature. The optical bandgap for a typical AlSb film is 1.52 eV, which is indicated from the optical absorption measurements.