Method of Moment is used to calculate vertical tail's radar cross section(RCS). The impact of leading-edge sweep angle, span and inclination on vertical tail's RCS is analyzed and then vertical tail's RCS curves and function expressions with leading-edge sweep angle, span and inclination are fitted by the calculation results. The results show that by optimizing the vertical tail leading-edge sweep angle, span, inclination and other geometrical parameters, can improve the stealth performance of the vertical tail. To optimize the design of the vertical tail of the stealth provide the technical foundation.