α-HgI2 crystal was grown using a static sublimation method in a self-designed vertical two-zone growth furnace. After 23 days growth, a single crystal of about 15 mm×12 mm×5 mm was obtained. The as-grown crystal was characterized by means of XRD and 4155 CVIV instrument, and the performance of the detector made with the as-grown HgI2 crystal was tested. The results indicate that excess iodine exists in the as-grown crystal, which can be removed effectively by heating at a feasible temperature. The resistivity of the as-grown crystal is about 1012 Ω·cm. The spectroscopy response to gamma ray (an uncollimated 241Am radiative source with the principal energy of 59.5 keV) of the detectors shows that the energy resolution is 14.6% corresponding to FWHM8.69 keV at room temperature