The present invention provides a method for installing at least one sensor device within a rotor blade of a wind turbine. A first substantially planar light beam is emitted in the interior of the rotor blade. Finally, at least one second substantially planar light beam is emitted in the interior of the rotor blade, wherein the plane of the first planar light beam is oriented at a predetermined angle to the plane of the second planar light beam. Further, the planes of the first and second planar light beams are aligned on the blade flange of the rotor blade. At least one sensor device is subsequently aligned in reference to the planar light beams.