The invention relates to an automobile renting method and provides an automobile renting system and method convenient for returning an automobile. An information center is communicated with an onboard terminal and a mobile phone in real time, the information center loads parking data of the automobile to be rented to a GPS navigation map of the mobile phone of a user to guide the user to find a standby automobile nearby, the user to use the automobile only needs to close a non-contact radio-frequency card integrated with the mobile phone to an automobile door, and the automobile door is unlocked automatically. The legal user gets on the automobile and inputs a user ignition code into a GPS display of the onboard terminal, and then the automobile can be ignited and started after the code is certified as authentic, thus achieving convenient automobile taking at a parking space. In the driving process, the user can inquire a destination and available conditions of the parking spaces nearby along the line on an onboard GPS navigation instrument so as to park in the parking space in time. After parking and switching off a motor, the user can conveniently select returning and keeping ofthe automobile, and after the user leaves the rented automobile for certain distance, the automobile door is locked automatically.