The analysis of different models, which describe the process of interphase friction in filled systems, shows that a special interest makes a clarification of laws of friction between a polymeric matrix and a hard inclusion. Based on experimental studies, we obtain a nonlinear equation, which relates friction force, pressure, and slip velocity. Using an experimentally obtained law of friction, we propose an algorithm which describes the process of interphase friction in the case of constant contact between the matrix and the hard inclusion as well as in the case of detachment of the matrix from the hard inclusion.