Radiation effects of 1MeV electron on middle wavelength Hg 1-xCd xTe photoconductive detectors were studied. Room and liquid nitrogen temperatures resistance, response spectrum, current responsivity and detectivity were measured before and after irradiation. It is observed that after irradiation, the detectors’ peak and cutoff wavelength move towards short wavelength; the room temperature resistance and current responsivity become decreasing when irradiation dosage is larger than 10 15/cm 2; the detectivity doesn’t show a monotonical change owing to the influnce of noise.