The invention discloses a drive axle assembly of a beam transporting vehicle. The drive axle assembly comprises a front drive axle housing, a rear drive axle housing, a first balance beam and a second balance beam. First axle shaft sleeves are arranged on the inner sides of the two ends of the front drive axle housing correspondingly; a first differential mechanism is arranged in a cavity of the front drive axle housing; the two ends of the first differential mechanism are both connected with first axle shafts; and the ends, penetrating through the first axle shaft sleeves and located on the outer side of the front drive axle housing, of the first axle shafts are provided with first hubs. Second axle shaft sleeves are arranged on the inner sides of the two ends of the rear drive axle housing correspondingly; a second differential mechanism is arranged in a cavity of the rear drive axle housing; the two ends of the second differential mechanism are both connected with second axle shafts; and the ends, penetrating through the second axle shaft sleeves and located on the outer side of the rear drive axle housing, of the second axle shafts are provided with second hubs. The gear ratio of the first differential mechanism is larger than that of the second differential mechanism; and the first differential mechanism is connected with the second differential mechanism through a drive device. The drive axle assembly of the beam transporting vehicle can reduce the friction of tyres and the ground so as to enable the beam transporting vehicle to operate safely and stably.