The invention discloses a parking management system based on the Internet of Things technology and its management method. The parking management system comprises: a mobile client APP, a database module, an image processing module, a motor control module and a gravity-sensing module. The main working steps include that the client APP makes a parking reservation, and when the user subscribes successfully and enters the parking lot, the mobile client APP automatically navigates the user to the reserved parking space. The image recognition module identifies the vehicle information, and the vehicle can park after identification. The gravity sensing system detects whether the vehicle is leaving or not, and if the vehicle leaves, informs the motor control module to control the image recognition module to rise. On this basis, the system can set the user's use of trust, and according to the user's behavior can make adjustments to its trust. The parking management system mainly aims at realizing the intelligent parking and charging management of the parking lot, optimizing the parking process, improving the service level and facilitating the parking of the owners.