The invention provides a traction method of a rail traction vehicle. A first traction trolley of a traction vehicle used for providing the traction force is tightly clamped on a rail; the first traction trolley simultaneously locks a first chain transmission mechanism or a second traction trolley locks a second chain transmission mechanism so that the position of one point on a chain in the chaintransmission mechanism relative to the traction trolley is not changed, so that the traction vehicle is driven to forwards move; the clamping state of the first traction trolley on the rail is relieved; the second traction trolley of the traction vehicle is tightly clamped onto the rail; the locking state of the first chain transmission mechanism and the second chain transmission mechanism is correspondingly changed so as to drive the traction vehicle to continuously and forwards move. The traction method of the railway traction vehicle has the advantages that the used traction vehicle has light self weight and lower energy consumption; good adaptability is realized on the heavy loading traction work conditions.