A security inspection apparatus and a method of controlling the same are described. An example security inspection apparatus includes a bottom plate configured to carry an inspected object and a two-dimensional multi-input multi-output array panel, including at least one two-dimensional multi-input multi-output sub-array. Each two-dimensional multi-input multi-output sub-array includes transmitting antennas and receiving antennas arranged such that equivalent phase centers are arranged in a two-dimensional array. The security inspection apparatus includes a control circuit configured to control the transmitting antennas to transmit a detection signal in a form of an electromagnetic wave to the inspected object in a preset order, and to control the receiving antennas to receive an echo signal from the inspected object. The security inspection apparatus includes a signal processing device configured to reconstruct an image of an inspected object based on an echo signal received and a display device configured to display the reconstructed image.