An identity verification method performed by an identity verification system comprising a collection device and a server, the method comprising: obtaining, by the collection device, a real-time face image of a user located in a specified area outside a verification area, comprising: obtaining, by the collection device, a real-time image in the specified area, wherein the real-time image is a video containing several consecutive frames of images; and whenever a specified period elapses, performing the following steps by the collection device: extracting, from the real-time image, a first frame of image, and extracting, from the first frame of image, a first face image as the real-time face image of the user located in the specified area only if a size of the first face image falls within a specified size range; sending, by the collection device, the real-time face image of the user located in the specified area to the server for storage; storing, by the server, the real-time face image of the user located in the specified area; obtaining, by the collection device, an identification provided by a user who enters the verification area from the specified area; sending, by the collection device, the identification to the server; obtaining, by the server and based on the identification, a pre-stored face image corresponding to the identification; and performing, by the server and based on each real-time face image stored by the server and the pre-stored face image, identity verification on the user who enters the verification area from the specified area, wherein the specified size range is determined based on a size of the specified area, a positional relationship between the specified area and the verification area, and/or photographing parameters of a camera of the collection device to limit the quantity of real-time face images that need to be stored by the server and subsequently compared by the server to the pre-stored face image. obtaining, by the collection device, a real-time face image of a user located in a specified area outside a verification area, comprising: obtaining, by the collection device, a real-time image in the specified area, wherein the real-time image is a video containing several consecutive frames of images; and whenever a specified period elapses, performing the following steps by the collection device: extracting, from the real-time image, a first frame of image, and extracting, from the first frame of image, a first face image as the real-time face image of the user located in the specified area only if a size of the first face image falls within a specified size range; obtaining, by the collection device, a real-time image in the specified area, wherein the real-time image is a video containing several consecutive frames of images; and whenever a specified period elapses, performing the following steps by the collection device: extracting, from the real-time image, a first frame of image, and extracting, from the first frame of image, a first face image as the real-time face image of the user located in the specified area only if a size of extracting, from the real-time image, a first frame of image, and extracting, from the first frame of image, a first face image as the real-time face image of the user located in the specified area only if a size of the first face image falls within a specified size range; sending, by the collection device, the real-time face image of the user located in the specified area to the server for storage; storing, by the server, the real-time face image of the user located in the specified area; obtaining, by the collection device, an identification provided by a user who enters the verification area from the specified area; sending, by the collection device, the identification to the server; obtaining, by the server and based on the identification, a pre-stored face image corresponding to the identification; and performing, by the server and based on each real-time face image stored by the server and the pre-stored face image, identity verification on the user who enters the verification area from the specified area, wherein the specified size range is determined based on a size of the specified area, a positional relationship between the specified area and the verification area, and/or photographing parameters of a camera of the collection device to limit the quantity of real-time face images that need to be stored by the server and subsequently compared by the server to the pre-stored face image.