Based on theoretic analysis of the horsehead failure mechanism, horsehead support is simulated with finite element method of three dimensional elastic-plasticity, and the effect of horsehead's stability under three supporting circumstances is also studied. It is considered that anchor rod's consolidating function for adjacent rock can't be ignored. Moreover neither single-rigid supporting nor single-flexible supporting is applicable to the horsehead, while secondary supporting of putting flexibility before rigidity is relatively ideal. This resulting conclusion offers the theoretic basis for selecting design schemes properly and has the specific significance for works' design and construction.