Abstract: During the robotic milling process of low-stiffness components, both the robot and workpiece exhibit flexible characteristics that can induce significant elastic deformations under milling forces, resulting in axial misalignment between the cutting tool and workpiece. This phenomenon severely compromises machining accuracy and surface quality. To address this issue, a modeling and compensation method that comprehensively considers the positioning error at the end of the robot and the deflection error of the robot-weak stiffness component is proposed. Firstly, a laser displacement sensor is employed for robot positioning error identification and deflection stiffness calibration, while finite element analysis is implemented to calculate the component deflection errors. Secondly, an integrated error model is subsequently established incorporating robot positioning errors, robot deflection errors, and workpiece deflection errors. Finally, based on this model, compensation for robotic end-face milling deflection errors is implemented. Experimental results demonstrate that compared with uncompensated machining, the proposed compensation method achieves 13.42% and 27.27% reductions in surface roughness and flatness error respectively, effectively enhancing surface machining quality.