The invention belongs to the technical field of mounting of arch centers of tunnels and provides an arch center mounting device for construction of the tunnel, which mainly comprises a chassis (9), a large arm (7), a small arm (6) and a workpiece clamping device, wherein the large arm (7) is arranged on the chassis (9), the small arm (6) is hinged at the end part of the large arm, a cylinder bodyof a small arm oil cylinder (8) is positioned on the large arm (7) and hinged with the large arm (7), and a piston of the small arm oil cylinder (8) is hinged with the end part of the small arm (6); the arch center mounting device is provided with a four-bar linkage and an overturning oil cylinder (4) for adjusting the pitching angle of a clamped workpiece; and the workpiece clamping device mainly comprises a body, a workpiece clamp (1), a clamp rotating mechanism, a clamp swinging mechanism and a clamp opening and closing driving mechanism. By adopting the device, the artificial labor intensity can be reduced, the fast mounting can be realized and the working efficiency can be improved.