The invention discloses a heavy frictional combined conveying line which is characterized by comprising a rail, a double-wheel driving device and / or a single-wheel driving device, and a dolly. The double-wheel driving device comprises motors, driving wheels, friction plates and a spring compressing device; the driving friction wheels are installed on driving shafts of the motors; friction objects are cast or installed at outer parts of the driving friction wheels; a gap is formed between the friction plates on the driving wheels; bases of the motors rotating in opposite directions are connected on a steel structure by using a base shaft and a bearing respectively; and the spring compressing device is connected with the bases of the two motors; centers of the base shaft of one motor and a motor driving shaft are not in a same line; the thickness of a dolly friction plate is slightly greater than the width of the gap; and the frictional force is adjusted by the spring compressing device. The heavy frictional combined conveying line has the advantages that firstly, work pieces carried by the conveying line are mainly carried by the rail, and the driving device provides the frictional force only; secondly, the conveying line can have a power and free function, the frictional force is easy to adjust, and the friction plates are easy to change and convenient to maintain; and thirdly, the conveying line comprises an upper layer and a lower layer, thereby being convenient for automatic production.