Abstract: Based on a nonlinear Mohr-Coulomb failure criterion and an associated flow rule, a kinematic admissible velocity field of failure mechanism of soil above an anchor plate was constructed, and the ultimate pullout force and failure mechanism of a shallow horizontal strip anchor plate were deduced through the upper bound limit analysis according to a variation principle. The influences of design parameters of anchor plates and soil parameters on ultimate pullout forces and failure mechanisms were analyzed, and the comparison between upper bound solution and different solutions was also conducted. The results reveal that the ultimate pullout force of an anchor plate will increase with the improvement of buried depth, initial cohesion and soil unit weight, that the failure mechanism of soil proposed is consistent with the test results of existing literatures, that the shape of failure surface depends on the magnitude of non-linear parameter m, and that non-linear parameter m also have a significant influence on the ultimate pullout force. With the improvement of parameter m, the ultimate pullout force will decrease nonlinearly, the rupture range of soil will also shrink, while the curvature of failure curved surface increases accordingly, and curved surface will degenerate into a flat surface when m is equal to 1. The upper bound solution is extremely close to existing solutions and numerical calculation solutions, which shows the effectiveness of this method, and provides some references for the design of anchor plates.