In the measurement of reflectivity and uniformity distribution of large-aperture optical component, using optical feedback cavity ring-down technique, 2-dimensional scan is required. Angular misalignment of the test component, which is induced during the scanning process, will influence the measurement accuracy. Based on the augmented matrix of the misalignment of optical resonator, the position of the light spots on the output cavity mirror and the influence on the high reflectivity measurement were calculated in the condition of the symmetric confocal resonator and stable resonator. In the symmetric confocal resonator, there was no drift of the odd light spots, while the drift of the even light spots was a constant for one angular misalignment. In the stable resonator, the drift of the odd and even light spots were reciprocating swing. The results show that the influence of the angular misalignment on the high reflectivity measurement is related to the position of the component and the cavity length. The methods of reducing the influence of the angular misalignment of the component on the measurement results are also presented.