Abstract: MWIR HgCdTe photoconductive detectors were irradiated with 1Mrad gamma dose, the devices were annealed at different temperature from 313 K to 333 K for different baking time. The body resistance，responsivity，response spectrum and detectivity of the devices were measured before and after irradiation and in different ways of annealing. The responsivity and detectivity of devices declined under the same conditions. The effects of annealing on the performance of the devices during the whole experiment were observed. The experiments indicate that proper annealing steps can recovery the responsivity of the devices partly. The 323 K may be the best temperature for annealing.