Abstract: <p>The performance of hyperbolic ion trap requires that each pole rod has a smooth surface and contour precision, while it’s not easy to achieve such results by conventional machining. In order to meet the requirements of smooth surface quality and sub-micron contour precision of hyperbolic ion trap rod, a non-circular section turning method based on slow tool servo technology is proposed. Firstly, the turning process of non-circular section was analyzed, and tool working angle was analyzed to avoid tool interference caused by large additive angle in non-circular section turning. The results showed that eccentric clamping could reduce tool additive angle. Secondly, factors concerned with contour accuracy were discussed, and the simulation results showed that tool centering error had a great influence on contour accuracy, this error needed to be controlled below 1 μm to realize sub-micron contour accuracy. Finally, experiment was carried out to testify and also measurement error was discussed due to measuring misalignment. Through trial fabrication, the contour error of hyperbolic surface can reach 0.3 μm.</p>