The invention discloses a sidewalk vehicle illegal parking detection method based on target detection and semantic segmentation, and belongs to the field of deep learning and computer vision, and themethod comprises the steps: respectively training a semantic segmentation network and a target detection network at a training stage, and obtaining a semantic segmentation model and a target detectionmodel; the method comprises the following steps of: extracting an urban road background image by using a Gaussian mixture background model; the method comprises the following steps: acquiring a semantic segmentation model, performing semantic segmentation by using a semantic segmentation algorithm and the semantic segmentation model to obtain a semantic segmentation graph, judging whether a camera rotates or not by using a perceptual hash algorithm, performing vehicle detection by using a target detection algorithm and the target detection model, marking a vehicle detection frame, and finallycomparing the vehicle detection frame with the semantic segmentation graph. The problems that an existing vehicle illegal parking detection method is high in misjudgment rate and poor in real-time performance, a sidewalk illegal parking area needs to be manually calibrated, and when a camera rotates, the illegal parking area needs to be manually calibrated again, so that the camera is not suitable for rotating are solved.