Abstract: Based on the theory of limit equilibrium of deformed body corresponding to the traditional theory of limit equilibrium of rigid-plastic body, the finite element contact simulation method is presented for computations of active earth pressures acting on L-shaped retaining walls with reduced friction coefficients of base bottoms. According to this method, the computations of the engineering cases by using the commercial non-linear finite element analysis program, i.e., ABAQUS are performed. The existence of the second sliding surfaces behind substantially planar retaining walls, which is once a theoretical supposition, is discovered and proven by the numerical simulation method. The positions of the first and second sliding surfaces behind L-shaped retaining walls that accord with the conditions of substantially planar retaining walls are revealed truly. The potential third sliding surfaces in backfills behind L-shaped retaining walls which do not strictly accord with the conditions of substantially planar retaining wall are also discovered. The present method is rigorous in theory, and it is shown by its comparisons with practical engineering cases that the distributions and magnitudes of active earth pressures acting on backs of L-shaped retaining walls can be obtained more accurately and reasonably by this method. It is more reliable than Rankine earth pressure theory which was conservative or unsafe for the calculations of the factors of safety against sliding and the factors of safety against overturning, respectively. Meanwhile, the present method is of high efficiency, so it will have a bright application prospect.