The present disclosure relates to a security inspection system and method using the three-dimensional holographic imaging technology. The system comprises: a body frame; a millimeter-wave transceiving module, disposed on the body frame; and at least two millimeter-wave switch antenna arrays, connected with the millimeter-wave transceiving module; the number of the millimeter-wave switch antenna arrays being the same as that of the scan areas; a scan driving device, configured to drive the at least two millimeter-wave switch antenna arrays to rotate along the same direction; a control device, configured to control the scan driving device to generate a rotation angle signal; and a parallel-image processing module, configured to synthesize a three-dimensional holographic image of an under-test object according to echo signals collected by the millimeter-wave transceiving module and spatial position information of the echo signals. The present disclosure simplifies the system structure and improves the imaging resolution.