This invention provides an ultra-precision turning apparatus for oblique off-axis ellipsoidal mirrors, comprising a base, an ellipsoidal mirror, and a
cutting tool. The base has a first side and a second side arranged opposite to each other. The first side is used to connect to the spindle of a turning
machine tool. The ellipsoidal mirror has an ellipsoidal surface to be machined, and the ellipsoidal mirror is detachably connected to the second side so that the rotation center axis of the ellipsoidal mirror coincides with the rotation center axis of the spindle. The
cutting tool includes a
tool holder and a
cutting head connected to the end of the
tool holder. The ultra-precision turning apparatus provided by this invention can be installed in conjunction with a turning
machine tool to achieve ultra-precision turning of oblique off-axis ellipsoidal mirrors. Compared with the traditional
polishing method for preparing oblique off-axis ellipsoidal mirrors, it is more efficient, lower in cost, and also has the advantages of high
machining accuracy, simple installation, and avoidance of
machining interference.