Abstract CaDyAlO4 (CDA) crystals with dimensions of Φ 25 × 28 mm3 were grown by the Czochralski method. The presence of a small amount of oxygen in the growth atmosphere will cause the coloration of CDA crystal, and correspondingly reduce the transmittance in the range of 400–730 nm. Rietveld structural refinement of XRD patterns revealed a slight difference in the unit cell parameters of the brown and yellow-green CDA crystals. The angular and temperature dependencies of the magnetic susceptibility were measured, indicating that CDA crystal has remarkable magnetic anisotropy and abnormal magnetic behavior in the a and c direction below 150 K. Faraday rotation characteristics of CDA crystal were investigated at room temperature. Verdet constant of CDA at 500–700 nm band is about 1.1 times as large as that of TGG, but only 0.69 fold of that for isostructural CaTbAlO4 (CTA). Based on the Van Vleck-Hebb theory, the effective transition wavelength and probability of three crystals were calculated and compared. The absorption and magnetic circular dichroism spectra (MCD) of 4f-4f transitions in Dy3+ ions in CDA were studied.