Abstract: The operation of marshalling of rail cars used to be low in efficiency for the reason that the number of each car pulling in or out of the station had to be recorded manually. To tackle this problem and improve the dispatching efficiency, a car number automatic identification system is developed. Practice shows with the use of the system the car number on the electronic label of each car can be automatically and accurately identified, and through collection of the coded information, automatic marshalling of cars is realized. It's use has led to improvement of dispatching efficiency and reduction of manpower and operating costs.