This paper introduces a novel decoupled geometric control method for quadrotor UAVs, based on the principles of incremental nonlinear dynamic inversion (INDI). The proposed method leverages differential flatness and INDI to linearize the nonlinearity of the UAV system, allowing for effective control of both translational and rotational movements. By applying INDI, the controller achieves strong tracking capabilities, particularly for large-angle yaw movements, while ensuring asymptotic convergence of attitude and position tracking errors. To validate the effectiveness of the proposed controller, simulations comparing it with an undecoupled geometric controller are conducted. The results demonstrate that the decoupled geometric control algorithm offers consistent performance and precise trajectory tracking.