Abstract: In this paper, a new method for the modeling and simulating of planar multi-body dynamics with friction-affected sliding joints is presented. Each friction-affected sliding joint is split into two unilateral constraints opposite to each other. The normal constraint equalities and tangential frictional forces are replaced by unilateral inequalities that are expressed in complementary form at acceleration level, so the absolute items of Lagrange multiplier in dynamic equations are avoided. LCP-based event-driven scheme is adopted. A new dimension-changeable matrix is introduced for describing the structure-dependent feature of the system. The simulation results show that the proposed method is effective.