To solve the problem that the existing star simulators are only concerned with the precision of star map simulation while neglects the sky background simulation, a high-precision static star simulator was designed under a uniform background of sky. In this paper, the components and operating principles of the star simulator were elaborated emphatically, and the optimal design method was also discussed in detail for the optical system. According to simulator's optical system which was featured with big lens and high precisions, the lens cone was designed to have a fixed, tube-in-tube structure. Moreover, in order to guarantee the precision of star map simulation, the laser direct writing technology was adopted to fabricate star testers with a precision exceeding ±1 μm. Test results indicated that the star map simulation precision of the designed high-precision static star simulator with a uniform sky background is greater than 3″and the sky background uniformity is larger than 95%. Therefore, it is able to satisfy requirements of high-precision ground calibration and functional test for navigation sensors.