For general attitude sensors, there is a deviation between the actual measurement results and design precision of non-on-orbit calibration equipment. In addition, they lack the simulation function for the target celestial bodys characteristics. In this work, we combined a polarization splitting prism and semi-reversing semi-transparent prism to complete liquid crystal on silicon (LCOS) optical splicing manner. With sub-pixel display technology, in which many pixels were used to express one feature point, a high-precision dynamic celestial simulator was designed for solving the problems mentioned above. First, the reasons for the low contrast ratio of two light valves in the traditional LCOS splicing manner were described in detail. Then, the improvement plan for the splicing structure was put forward. Subsequently, an apochromatic collimation optical system with small distortion and high imaging quality was designed. Furthermore, ideas and methods of sub-pixel display technology were investigated Finally, sub-pixel technology to conduct simulate a dynamic star map and target celestial body was employed. The results show that the contrast ratio of the LCOS splicing screen of a dynamic celestial body simulator, which can simulate a target celestial body, is high. Moreover, the angular travel error between two stars in the dynamic star map is less than ±6″. In addition, the stellar magnitude simulation context reaches eight continuous grades. The stellar magnitude simulation precision is better than ±0.3 mV. The results meet the precision requirements for feature point recognition of an attitude sensor. The high-precision dynamic celestial simulator may meet the basic requirements for ground precision calibration and functional testing of a sensor.