This research present to obtain optical turbulence structure and refractive index information a long a near
horizontal (0.035 Km) free space path length. Measurement the optical turbulence structure (Cn2), refractive index
(nr), Pressure and temperature for several case in winter, spring, summer and autumn. Optical measurements were
investigated using three different wavelengths of laser sources (808, 632 and 1064 nm) .we found the change in
refractive index is very small but the change in refractive index structure is very strong.