Gears are used to transmit power between two parts of the same machine or between two devices, often with a mechanical advantage that allows increasing or decreasing the rotational speed or torque from one shaft to another. As is commonly the case in the analysis of most tribological components, the key parameters of interest in gears are the lubricant film thickness, the dimensionless film parameter, and the coefficient of friction. The first two parameters are important in terms of reliability and damage, while the third parameter is a measure of the efficiency of the gear set in terms of the required power. In industrial applications, the friction coefficient between the moving contacting surfaces is of vital importance in terms of power loss. Another influential parameter in lubricated tribosystems is the roughness of the surfaces i.e. the micro geometrical irregularities of the surfaces. Gears usually operate under the mixed-lubrication regime. Hence, it is always of interest to predict the portion of load carried by asperities as well as friction coefficient. The aim of this research is to present a model that takes into consideration the surface properties, gear geometry, loading condition and velocity condition as the input and predicts the film thickness, friction coefficient and the subsurface stresses along the line of action (LoA). When two bodies having curved surfaces are pressed together, point or line contact changes to area contact, and the stresses developed in the two bodies are three dimensional. Contact-stress problems arise in the contact of a wheel and a rail, in automotive valve cams and tappets, in mating gear teeth, and in the action of rolling bearings. In this model, the contact of gear teeth at each point along the LoA is represented by the contact of two cylinders, where the radii of these cylinders vary along the LoA. The contact model for rough surfaces introduced by Greenwood and Williamson (1966) assumes that the asperities deform elastically, however, in reality when the contact pressure exceeds the yield strength of the material, elastic-plastic deformation occurs. The separation between the two rough surfaces is given by the film thickness which would exist between two smooth surfaces under the same conditions of load, speed and lubricant. In this research The model of zhao et al of rough surfaces in contact has been combined with Moes’ central film thickness equation and load-sharing concept of Johnson et al use to predicting the film thickness, friction coefficient load carried by film and load carried by asperity a long line of action. Finally subsurface stresses is obtained using the coefficient of friction and hertzian contact model. Finally by use the FEM modeling for contact problem of pinion and gear, then FEM results compared with the numerical solution. The comparison between the present model and the results from other published models shows an acceptable agreement. A parametric study on the effect of the load, speed and surface roughness on the coefficient of friction and asperities scaling factor is implemented. The main advantages of the model are that the model does not require solving the full EHL equations. Also, it generates reasonable results for rough surfaces. The results are in acceptable agreement with other works. This model can be used as a rapid .prediction for the gear performance. Keywords: Spur gear, Line of action, Load sharing concept, Friction coefficient and subsurface stresses.