The invention discloses a construction method for a large-area concrete weighbridge. The construction method comprises the steps of: dividing the locations of a construction water flowing section and a construction separation joint, erecting a weighbridge side template, installing a force transmission rod at a junction of the water flowing section, erecting a laser leveller, fixing a levelling staff, selecting a levelling base point, pouring concrete in a space surrounded by weighbridge templates, vibrating, compacting and levelling the weighbridge by the leveller, finishing surface conditioning and polishing of the concrete weighbridge before the final solidification of the concrete, maintaining the concrete weighbridge, cutting the construction separation joint within 24h, stuffing the construction separation joint and carrying out secondary maintenance. By the construction method, the technical problem that the whole levelling degree of the large-area weighbridge is very difficult to control is solved; the problems that the cost of later maintenance of the ground and the use quantity of the templates are very high since the construction joint of the large-area concrete weighbridge is very prone to breakage is solved; and the problems such as breakage along a warehouse dividing joint on the large-area concrete weighbridge, easy hollowing in the layered pouring of the weighbridge, easy cracking and the like are solved.