Rigorous analysis of the Base-Station (BS) antennas with reflector is made in this letter. The wire-grid modeling of BS antenna is established. In order to improve the solution accuracy and efficiency, some efficient techniques such as three-term sinusoidal interpolation basis function and discrete wavelet transform are used. Numerical examples considered here are the typical vertically polarized and the dual-polarized BS antennas. The calculated results for the vertically polarized BS antenna are in good agreement with the measured data, which show that the analysis modeling used is accurate and reliable.