A method of the three-hole optical observation is presented that can measure the chromatic dispersion angle with the advantage of overcoming the influence of out-of-focus images on the measurement results, especially those that are out-of-focus due to the ambient temperature change. This paper uses the refractive index model and the actual meteorological data to calculate the chromatic dispersion angles during the observation period for comparison and analysis to demonstrate the reliability of the optical observation. The optical observation results are generally consistent with the calculated results, but the local distribution is relatively discrete. Additionally, the optics method applies to the observation targets under arbitrary paths in the dynamic atmosphere, and the observed results can better reflect the real atmosphere condition of the chromatic dispersion angle, providing more accurate data for research in related fields.