The invention discloses a parking lot management system based on big data, thereby solving the problems of unreasonable parking space distribution and low working efficiency in the existing parking lot management system. The system comprises a server, a user recharging module, a parking space information module, an information acquisition module, an illegal parking detection module, a category distinguishing module, a road sign module, a lifting door and a display screen. The category distinguishing module of the parking lot management system automatically and reasonably distributes the parking spaces according to the parking scores of to-be-parked vehicles and grade classification of primarily selected parking spaces, so that customers with high parking scores enjoy relatively good parking spaces, and the customer satisfaction is high; the parking lot management system realizes unmanned management, is high in intelligence, can quickly respond according to vehicle types and different types, automatic quick opening and closing of the overhead door are realized, the working efficiency is improved effectively, and traffic jam at the entrance and exit of the parking lot is avoided.