The invention provides a system for assisting in catching a criminal by using an elevator. The system comprises a single chip microcomputer, a first camera, a memorizer and a network connection module; the first camera is used for shooting face images of passengers in a lift car, face image information of criminals is saved in the memorizer, and the single chip microcomputer is used for performingface recognition, sending alarm information to a public security system timely and guiding an elevator control system in being locked. A method for assisting in catching the criminal by using the elevator particularly comprises the steps that A, face recognition is performed on the passengers in the lift car; B, whether or not the criminal exists among the passengers is judged; C, whether or notgeneral people exist among the passengers; D, the elevator control system is locked; E, police commissioners arrive at the scene to catch the criminal. The system and method for assisting in catchingthe criminal by using the elevator has the advantages that personal identity verification can be performed on the passengers, and the criminal can be stuck in the elevator in appropriate conditions, thereby providing convenience for the public security to catch the criminal.