A two mirror aspheric optical system has been designed for soft X ray reduction lithography. The designed optics achieves a defraction MTF value of over 0.5 at 13 nm wavelength and at a spatial frequency of 5300 lines/mm capable of resolving <0.1 μm lines and spaces within a flat field of φ30 mm. The reduction ratio is 1/6, working F/# is 2.554 and the maximum distortion is 0.04%.