The contrastive experiment of back-scattering echo and beacon angle-of-arrival fluctuation was introduced. The experiment was used to validate that whether the back-scattering angle-of-arrival fluctuation can describe the atmosphere structure of refractive index Cn^2 by method of contract. The results prove that the back-scattering angle-of-arrival fluctuation can describe the atmospheric structure of refractive index Cn^2. And some contrastive parameters were analyzed.