MTF (Modulation Transfer Function) is useful to characterize the response of a linear imaging system, namely MTFs of the imaging systems and human eye determine the overall sharpness quality. Therefore various merits used MTF have been proposed and applied for evaluation of image quality. However, almost merit used MTF is not considered anisotropy properties of imaging system and human eye response.In this paper, dependence of the directivity of contrast sensitivity of human eye in various luminance, RGB color space and opponent color space is measured and analyzed. On the basis of those measured contrast sensitivities, two-dimensional MTF model of human eye is proposed and applied to designing and evaluate digital imaging system such as CCD array and digital color reproduction.