The ellipsoidal domes generate huge air resistance, which limits the operational performance of precise guided weapons. To reduce the air drag, the conicoidal conformal optical domes are investigated and a better surface shape of the dome is designed. The computational fluid dynamics method is adopted to compute the drag coefficients produced by the conicoidal conformal optical domes. The evaluation function of the drag coefficient is established. Based on the ray tracing theory, the evaluation function of imaging quality of conformal domes is modeled by putting the average root mean square wavefront errors of different fields of regards to the evaluation parameters. Based on the radar scattering theory, the radar scattering cross sections of conformal domes are computed. The evaluation function of radar scattering property is established. Taking the air resistance, imaging quality and radar scattering property into account, the evaluation function of comprehensive performance of the conicoidal conformal optical domes is established. The parabolic dome with the fineness ratio of 1.5 is proved to possess better comprehensive performance. Compared with the ellipsoidal dome, the parabolic dome established in this paper just produces 2/3 air resistance of the ellipsoidal dome does.