The invention discloses a vehicle-mounted card type highway traffic flow statistics and traffic jam forecasting method. A vehicle-mounted card (1) and a plurality of electronic base stations (2) mounted on each section of a highway are used in the method. The electronic base stations (2) communicate with the passing vehicle-mounted card (1) through short-distance telecommunication, and the card number, the vehicle type, the driving direction and the passing time of the vehicle-mounted card are obtained, subjected to statistics and sent to a superior center through a long-distance radio data transmission circuit in a timed, quantified or remote control manner to serve as the bases for a traffic jam forecasting signal; the electronic base stations are low in power consumption and small in size, can be conveniently mounted on each section of the highway according to the traffic flow monitoring requirements, and can work in all weathers without weather environment influence; the superior center can timely obtain or take the traffic flow of each monitoring point and send out a traffic jam forecast to a highway administration department according to a set traffic flow threshold.