Airborne area-array whisk-broom imaging systems typically adopt constant-speed scanning schemes. For large-inertia scanning systems, constant-speed scanning requires substantial time to complete the reversal motion, reducing the system's adaptability to high-speed reversal scanning and decreasing scanning efficiency. This study proposes a novel sinusoidal variable-speed roll scanning strategy, which reduces abrupt changes in speed and acceleration, minimizing time loss during reversals. Based on the forward image motion compensation strategy in the pitch direction, we establish a line-of-sight (LOS) position calculation model with vertical flight path correction (VFPC), ensuring that the central LOS of the scanned image remains stable on the same horizontal line, facilitating accurate image stitching in whisk-broom imaging. Through theoretical analysis and simulation experiments, the proposed method improves scanning efficiency by approximately 18.6% at a 90° whisk-broom imaging angle under the same speed height ratio conditions. The new VFPC method enables wide-field, high-resolution imaging, achieving single-line LOS horizontal stability with an accuracy of better than 0.4 mrad. The research is of great significance to promote the further development of airborne area-array whisk-broom imaging technology toward wider fields of view, higher speed height ratios, and greater scanning efficiency.