Abstract: Based on a power spectrum of non-Kolmogorov turbulence developed by A S Gurvich et al, the variance of angle-of-arrival (AOA) fluctuations was derived. The concise closed-form expression was obtained and used to analyze the joint influence of Kolmogorov tropospheric turbulence and non-Kolmogorov stratospheric one on the fluctuations in the angle of arrival (AOA) of starlight. It is shown that the AOA fluctuations of starlight were mainly determined by Kolmogorov tropospheric turbulence. And the non-Kolmogorov stratospheric turbulence was responsible for 5-14 percent of the total of AOA fluctuations for different receiver apertures in weak fluctuations regime. In addition, the AOA fluctuations induced by non-Kolmogorov turbulence depended on the receiver aperture and the outer scale and the intensity of non-Kolmogorov turbulence.