The invention discloses a control method and a control system for erecting and straightening a large structural component. The method comprises the following steps: step 1, erecting the structural component; step 2, obtaining an erecting angle; step 3, judging whether the erecting angle is larger than or equal to a first threshold value or not; if yes, executing the step 6; and if not, executing the step 4; step 4, calculating erecting angular velocity; step 5, controlling the action of a hydraulic oil cylinder based on the erecting angular velocity, and returning to the step 2; step 6, obtaining perpendicularity; and step 7 judging whether the perpendicularity is larger than or equal to a second threshold value or not; if yes, controlling the action of the hydraulic oil cylinder based on the perpendicularity, and then, returning to the step 6; and if not, ending. The system comprises a main controller, a valve controller, a photoelectric encoder, a level gauge and the like. The control method and the control system can realize accurate locating and rapid and stable erecting of the large structural component, greatly reduce erecting and straightening time, and effectively reduce the dependence of the erecting and straightening process of the large structural component on a high-precision hardware product.