The utility model relates to an assembly type structure's construction field specifically is a wide -angle len for installation of assembled concrete member, characterized by: including wide angle lens, mirror holders, connecting axle and action bars, mirror holders includes picture frame, rubber pad and hollow sleeve pipe, the wide angle lens sets up in the picture frame, and the rubber pad inlays on the contact surface of picture frame and wide angle lens, and hollow sleeve pipe setting is in one side of picture frame, and it is connected bottom the connecting axle, the top AND operation pole of connecting axle is connected. This wide -angle len adopts above -mentioned structure, and it makes the angle of whole wide -angle len to adjust at will through the cardan shaft, and the telescopic action bars also makes the adjustable length of whole wide -angle len whole, so can be conveniently shen ru survey the wide -angle len to sleeve or component bottom, improve the security of strip operation.