This study deal with the action of gravity on the single and the double thin layer of non-Newtonian fluid which was passed over the belt. b The descriptive study is mainly focused on the effects of the fluid rheology. We paid special attention to the structuring of models for describing the behavior of the movement of the thin films. Specially those fluid films having high molecular weight which consists of greater complexities. Navier-stokes equations cannot do justice in describing the behavior of such fluids to the extreme. To describe the properties of all non-Newtonian fluids in a single constitutive equation sound ridiculous due to the great variety of such fluids which makes it difficult to design one wholesome equation for it. To cope up with this complexity, varieties of models have been presented in the literature. This study is conducted with several elastic fluid models such as second and third grade fluid models and inelastic power law fluid model. Highly non-linear relationships in term of differential equations arise as a result of modeling rheological fluids in the domain of a problem. Comprehensive study of a skin friction, volume, flux, vorticity, near boundary layer, diffusion of temperature is conducted for such complex nature of fluids. Moreover the effect of oscillation on the above features in case of unsteady layers is discussed in detail.