Abstract: The present disclosure provides an image acquisition method and apparatus and a video monitoring method and system. The image acquisition method is applied in an image acquisition apparatus in a video monitoring system, wherein the image acquisition apparatus is provided with a WiFi detector and an image capturing component; the method comprises: using the image capturing component to acquire a human image containing a human body feature in a target environment; using the WiFi detector to detect and obtain unique identification information of at least one WiFi terminal located in the target environment; enabling the human image and the unique identification information of the at least one WiFi terminal to correspond to each other to generate image data of the human image containing the human body feature and the unique identification information.