A method and a system for contraband detection in an object using photoneutrons and x-rays includes an x-ray generator that generates an x-ray main beam including a first x-ray beam and a second x-ray beam, the first x-ray beam being directed to pass through the object. A photoneutron conversion target is arranged to receive the second x-ray beam so as to generate photoneutrons, the photoneutrons being directed to enter the object and react with the object to emit characteristic γ-rays. An x-ray detecting arrangement is arranged to receive the first x-ray beam that has passed through the object in order to perform x-ray imaging detection of the detected object. A γ-ray detecting arrangement is arranged to receive the characteristic γ-rays in order to perform neutron detection of the object based on the characteristic γ-rays. The x-ray imaging detection and the neutron detection are simultaneously performed.