The invention discloses an automobile intelligent speed limiting system and an automobile speed limiting method, and relates to the technical field of automobile safety driving assistance. The automobile intelligent speed limiting system and the automobile speed limiting method can improve accuracy of speed limiting identification recognition and improve driving safety of a driver. The automobile intelligent speed limiting system comprises a camera, an intelligent navigation device, an automobile body sensor and a controller, wherein the camera can recognize road traffic identification boards and extract road traffic identification information through the image processing technology, the intelligent navigation device can provide current road information, navigation route information and national or regional traffic road speed limiting law related information in real time, the automobile body sensor can provide automobile body information in real time, a traffic speed limiting identification database is set up in the controller, the input end of the controller is connected with the camera, the intelligent navigation device and the automobile body sensor, and the output end of the controller is connected with an automobile instrument and an engine ECU. The automobile intelligent speed limiting system is used for assisting in limiting the speed of the automobile.