The invention discloses a millimeter wave radiometer receiver for target radiation characteristic measurement, and a millimeter wave target radiation characteristic measuring method. The receiver comprises an antenna, an electric-control attenuator, a directional coupler, a noise source, a noise source modulator, an isolator, a local oscillator source, a mixer, an intermediate-frequency preamplifier, a band-pass filter, a main intermediate frequency amplifier, a square-law detector, a video amplifier, an integrator, a signal collecting and processing unit and a thermometer. During the measurement, the electric-control attenuator is controlled to be in an unattenuated state and a maximum attenuated state, and the signal output by the receiver is collected and processed, so that the target millimeter wave radiation characteristic measurement is achieved. The receiver of the invention solves the problems that the performance of the receiver for the noise adding type millimeter wave target radiation characteristic measurement is largely restricted by a radio frequency switch, a video signal processing circuit is complex, the debugging is difficult and the flexibility is poor. The complexity and the cost of the receiver are reduced while the reliability of the receiver is improved.