A vehicle monitoring system comprising: a camera module configured to capture more than one first image and more than one second image after a vehicle is started, wherein when an infrared sensor outside the vehicle door senses approaching of a person, the camera module is triggered to collect the first image containing persons getting on the vehicle, when an infrared sensor inside a vehicle door senses approaching of a person, the camera module is triggered to collect the second image containing persons getting off the vehicle; a processing module connected to the camera module and configured to: perform face analysis on the first image to determine the persons getting on the vehicle, perform face analysis on the second image to determine the persons getting off the vehicle, and match each of the persons getting on the vehicle with each of the persons getting off the vehicle in turn; and a reminder module connected to the processing module and configured to: push a message that a passenger is left in the vehicle to a driver if there is the person getting on the vehicle who is not able to be matched with the persons getting off the vehicle, so as to remind the driver that this person is still left in the current vehicle; wherein the processing module is further configured to identify faces included in the first image and the second image and determine whether a person corresponding to a face contained in the first image or the second image is a person getting on the vehicle or a person getting off the vehicle based on an orientation of the face contained in the first image or the second image; characterized in that: the processing module is further configured to deduplicate faces of the persons getting on the vehicle and faces of the persons getting off the vehicle by deduplicating the same face information collected multiple times in a preset short time. a camera module configured to capture more than one first image and more than one second image after a vehicle is started, wherein when an infrared sensor outside the vehicle door senses approaching of a person, the camera module is triggered to collect the first image containing persons getting on the vehicle, when an infrared sensor inside a vehicle door senses approaching of a person, the camera module is triggered to collect the second image containing persons getting off the vehicle; a processing module connected to the camera module and configured to: perform face analysis on the first image to determine the persons getting on the vehicle, perform face analysis on the second image to determine the persons getting off the vehicle, and match each of the persons getting on the vehicle with each of the persons getting off the vehicle in turn; and a reminder module connected to the processing module and configured to: push a message that a passenger is left in the vehicle to a driver if there is the person getting on the vehicle who is not able to be matched with the persons getting off the vehicle, so as to remind the driver that this person is still left in the current vehicle; wherein the processing module is further configured to identify faces included in the first image and the second image and determine whether a person corresponding to a face contained in the first image or the second image is a person getting on the vehicle or a person getting off the vehicle based on an orientation of the face contained in the first image or the second image; characterized in that: the processing module is further configured to deduplicate faces of the persons getting on the vehicle and faces of the persons getting off the vehicle by deduplicating the same face information collected multiple times in a preset short time.