The invention relates to an automatic parking system based on a mobile robot trolley. The automatic parking system is mainly and technically characterized by comprising a parking lot, the mobile robot trolley and a parking lot intelligent control system, wherein a plurality of rows of parking spaces, a plurality of lines of parking spaces and mobile robot trolley rotating spaces are arranged on the ground of the parking lot, a non-rail type vehicle guide device is paved on the ground of the parking lot, a vehicle access chamber and a center control chamber are arranged in the parking lot, the parking lot intelligent control system is arranged in the center control chamber and is connected with the mobile robot trolley and the vehicle access chamber, and the mobile robot trolley supports vehicles to be accessed for realizing the vehicle access through being controlled by the parking lot intelligent control system. The automatic parking system has the advantages that the design is reasonable, and the flexible dispatching on the vehicles to be accessed and the flexible vehicle access can be carried out through the mobile robot trolley and the corresponding control system, so the functions of high-density storage, fast response and safe service are realized, and the automatic parking system has the characteristics that the building and maintenance cost is low, the access is convenient, the energy is saved, the environment is protected, and the like.