Five-axis flank milling plays a crucial role in manufacturing due to its high efficiency and accuracy advantages. However, errors are inevitably introduced during the machining process from various sources. Herein, a Double-Point-Mirror (DPM) method is proposed for flank milling of ruled surfaces, which consists of four key steps. Firstly, the error distribution of the semi-finish surface is obtained by linear spatial fitting of the theoretical points and the actual measuring points. Secondly, the combination of the mirrored tool orientation and the mirrored tool tip position is calculated using the proposed DPM method. Thirdly, the connections between the combination and coordinate are established using the Fourier fitting method. Finally, the mirrored finishing toolpath is generated by replacing the original toolpath. The results of the experiment demonstrate that the proposed strategy and the DPM method can significantly improve the accuracy of flank milling. [ABSTRACT FROM AUTHOR]