In this thesis, we study to reduce two-, three- and four-wavelength chromatic aberrations with use of a prism system which consists of a two-prism set and a three-prism set. In choosing glasses, we apply a conventional formula and figure scheme to select appropriate glasses so that chromatic aberration can be reduced for other wavelengths and the deviation angle in each prism is small. In order to judge the validity of proposed method based on the paraxial formula, we apply real ray tracing in computer simulation. We find that the result by paraxial formula and that by real ray tracing are close to each other and the chromatic aberrations are small in both cases. The results show that the proposed method based on paraxial formula is trustable.