The columns in classical architecture take especially important roles for their visual effects. The authors show through experiments by simulation of computer graphics how tapering, fluting and enthasis of the Parthenon columns effect on visual perception. As a result, they have found that the upward tapering of the columns gives the strongest influence on the visual impression of the building compared with other two. The enthasis, which is very subtle in the Parthenon, also gives the visual effects in fact, although it looks almost unrecognizable.