Through this paper we discussed some theoretical aspects related to the change in As content in the compound AsxSe100-x . We also presented a discussion on the XRD and optical analyses of the investigated system. The XRD analysis of AsxSe100- x (5 ≤ x ≤ 50) compositions emphases the amorphous structure of the prepared samples either in bulk or in thin film form. In the present compound of AsxSe100-x, the rigidity percolation threshold (RPT) occurs at As=40 at.%. The optical absorption coefficient (α) for the as-deposited films was calculated using spectrophotometer measurements of the transmittance (T) and reflectance (R) at normal incidence of light in the wavelength range 350–2500 nm. The optical band gap was found to be indirect allowed for all AsSe thin films of thickness 850 nm. The behavior of optical gap of the deposited AsxSe100-x films was found to decrease with increasing of As concentration (upto 40 at.%) and this behavior is interpreted in terms of Mott and Davis model and the chemical-bond approach (CBA). The high frequency dielectric constant (e1) and the ratios of the carrier concentration to the effective mass (N/m*) were also determined for the as-deposited films. The dispersion of the refractive index is discussed in terms of the single-oscillator model. The oscillator energy Eo and the dispersion energy Ed were obtained.