A high-precision reference spherical lens is designed. The F number of the lens is 0.82. The wavefront PV value is 0.09 λ and RMS value is 0.028 λ. The slope of wavefront is 11 μrad. We calculate the retrace error of the reference spherical lens. The maximum of retrace error is 0.29 nm. A part of surface is measured with the reference spherical lens. The results show that precision of 1 nm can be reached.