The invention provides a bidirectional laser welding system. The bidirectional laser welding system comprises a first steel structure, a laser head, a first working machine table, a second working machine table and a control device; the first steel structure is provided with a laser head walking shaft parallel to ground; the laser head is arranged to move along the laser head walking shaft; a reference line is arranged at the middle point of the laser head walking shaft, is perpendicular to the laser head walking shaft and is parallel to the ground; a plane passing through the reference line and perpendicular to the ground is defined as a second reference plane; the first working machine table and the second working machine table are the same in structure; and the first working machine table and the second working machine table are symmetrically arranged relative to the second reference plane. The bidirectional laser welding system provides two working machine tables, when one working machine table completes the welding procedure, the other working machine table completes the part discharging and feeding procedures, and therefore the laser head can be in a full-load working state, and the double capacity can be achieved.