Asymptotic waveform evaluation(AWE) technique in conjunction with equivalent dipole-moment(EDM) method is applied to obtain radar cross section(RCS) of an arbitrarily shaped three-dimensional(3-D) perfect electric conductor(PEC) over a frequency band.EDM method is used to achieve fast filling of impedance matrix and more derivative matrices.Inner and outer iterative near field preconditioning technique is used to solve matrix equation.Wide-band radar cross section is achieved by using AWE technique.Numerical results show that the computational efficiency is improved significantly with ensuring accuracy.