In order to test the algorithms of star map identification and the performance of star sensor by simulating star map on the ground, a new and high-speed method for simulating star map is presented. This method makes use of the property of sectional circle and fixed field to divide the unit celestial according to three orthogonal axis planes and derive the angles between the vectors of stars and the axis planes based on latitude and longitude value as the condition for selecting stars. And then, star map can be simulated according to the principle of coordinate transformation. In order to verify the advantages of the proposed method compared with current methods, a lot of simulation is conducted. The simulation results show that compared with current common star map simulation methods, the proposed method guarantees the accuracy of choosing guide stars and its speed of choosing guide stars is three times faster than other methods.