The present invention relates to a radionuclide activating rate measurement device and method. The device comprises a trap type HPGe detector, an absorbing body used for absorbing the low-energy gammaand X rays and a measurement source container. The absorbing body is located in a trap of the trap type HPGe detector, the measurement source container is located in an inner cavity of the absorbingbody, the measurement source solution is located in the measurement source container, and the absorbing body and the measurement source container are both circular cylinders. The activating rate measurement method of the device mainly comprises the steps of 1) utilizing N nuclides to prepare the efficiency calibration solution; 2) measuring the detection efficiency in the efficiency calibration solution or the gamma-ray energy; 3) obtaining the gamma-ray energy of the to-be-measured X nuclide and the detection efficiency of the gamma-rays; 4) calculating the activity of the to-be-measured X solution; 5) calculating the activating rate via the activity. According to the present invention, by utilizing the efficiency calibration solution of various nuclides of which the decay schemes are simple and the activities are known, the activity of the target nuclide of which the decay scheme is complex is measured accurately.