The invention provides a parking lot management system, which is characterized by comprising an entity class module, a login module, a common user module, a member user module, an access management user module and a background management module, wherein the entity class module corresponds to a list of databases, and realizes complete mapping of database entities in a LINQToSQL class mode; the login module realizes login of member users, access management staff and background management staff; the common user module realizes basic parking space query, parking space guidance and public transport line query; the member user module realizes a parking space reservation and information management function of member users; the access management user module comprises vehicle incoming management and outgoing management, and an incoming management module comprises three types of service objects which are temporary users, member users who do not reserve a parking space and member users who reserve a parking space; and the background management module realizes functions of changing or setting the parking unit price, parking space out-of-service management and parking record query.