The invention relates to a vehicle-mounted crane limiting protection system and an automobile crane. The vehicle-mounted crane limiting protection system comprises operating levers, ultrasonic sensorsfor detecting the action of the operating levers, a controller, a force limiter, an electromagnetic valve, a main hook height limiting switch, an auxiliary hook height limiting switch, a main three-ring protector, and an auxiliary three-ring protector. When the crane encounters faults such as overwinding, over-discharging and overload during hoisting operation, the controller limits the operatinglevers to act towards the dangerous direction by controlling the electromagnetic valve to be powered on and powered off. Due to the fact that the ultrasonic sensor is installed behind each operatinglever, the controller can judge the total working direction of the operating levers according to the ultrasonic sensors; when the operating levers act towards the dangerous direction, all the action electromagnetic valves are powered on to unload, and the crane can only act towards the safe direction. The intelligent release system for limiting protection is easy to operate, safe, reliable and high in intelligent degree.