FADS(Flush Air Data System) had been used in various aircraft, showing the advantages of less interference on flow field, thermal and stealth characteristics of the aircraft. Numerical computations based on Newton model and filtering algorithm were conducted to investigate the orifices distribution effects on Accuracies of FADS. Virtual flight path covering Mach number 4.3-15.79, height 25-70 kilometers was defined. Spherical nose was presented for FADS orifices arrangement. Results of clock angle effect, cone angle effect and asymmetric distribution effect were presented and analyzed. Computational results showed that increasing the number of pressure points along the circumference can improve the measurement Accuracies of the FADS system. However, there is a threshold value. When the number of pressure points is the same, increasing the cone angle can significantly improve the measurement Accuracies of FADS. The asymmetric distribution of the orifices has no effect on the measurement Accuracies.