A millimeter wave/terahertz wave imaging apparatus, comprising a quasi-optical assembly, a millimeter wave/terahertz wave detector array, a data processing device and a calibration source, wherein the quasi-optical assembly is configured to reflect a millimeter wave/terahertz wave radiated or reflected by a first inspected object and a second inspected object and converge the millimeter wave/terahertz wave onto the millimeter wave/terahertz wave detector array, wherein the quasi-optical assembly comprises a reflector; the first inspected object and the second inspected object are respectively located on opposite sides of the reflector, and the reflector is rotatable about a horizontal axis to respectively receive and reflect a millimeter wave/terahertz wave from parts of the first inspected object at different vertical positions of a first field of view and a millimeter wave/terahertz wave from parts of the second inspected object at different vertical positions of a second field of view; wherein the millimeter wave/terahertz wave detector array is configured to receive the millimeter wave/terahertz wave from the quasi-optical assembly; wherein the data processing device is connected to the millimeter wave/terahertz wave detector array so as to respectively receive image data for the first inspected object and image data for the second inspected object from the millimeter wave/terahertz wave detector array and generate respective millimeter wave/terahertz wave images; and characterized in that the calibration source is provided on an object plane of the quasi-optical assembly, wherein the data processing device is configured to receive calibration data for the calibration source from the millimeter wave/terahertz wave detector array, and update the image data for the first inspected object and the image data for the second inspected object based on the calibration data received, wherein a length direction of the calibration source is parallel to the horizontal axis of the reflector, and a length of the calibration source is greater than or equal to a size of a field of view of the millimeter wave/terahertz wave detector array in a direction parallel to the horizontal axis. wherein the quasi-optical assembly is configured to reflect a millimeter wave/terahertz wave radiated or reflected by a first inspected object and a second inspected object and converge the millimeter wave/terahertz wave onto the millimeter wave/terahertz wave detector array, wherein the quasi-optical assembly comprises a reflector; the first inspected object and the second inspected object are respectively located on opposite sides of the reflector, and the reflector is rotatable about a horizontal axis to respectively receive and reflect a millimeter wave/terahertz wave from parts of the first inspected object at different vertical positions of a first field of view and a millimeter wave/terahertz wave from parts of the second inspected object at different vertical positions of a second field of view; wherein the millimeter wave/terahertz wave detector array is configured to receive the millimeter wave/terahertz wave from the quasi-optical assembly; wherein the data processing device is connected to the millimeter wave/terahertz wave detector array so as to respectively receive image data for the first inspected object and image data for the second inspected object from the millimeter wave/terahertz wave detector array and generate respective millimeter wave/terahertz wave images; and characterized in that the calibration source is provided on an object plane of the quasi-optical assembly, wherein the data processing device is configured to receive calibration data for the calibration source from the millimeter wave/terahertz wave detector array, and update the image data for the first inspected object and the image data for the second inspected object based on the calibration data received, wherein a length direction of the calibration source is parallel to the horizontal axis of the reflector, and a length of the calibration source is greater than or equal to a size of a field of view of the millimeter wave/terahertz wave detector array in a direction parallel to the horizontal axis.