||this article we are concerned with the dynamical instability of liquid crystals induced by applied magnetic fields, which is the so-called Freedericksz transition. The model under consideration is the simplified Ericksen-Leslie system for a nematic liquid crystal in a magnetic field. We showed that if the magnetic field strength exceeds a threshold, any global solution converges exponentially to a unique nontrivial equilibrium solution. Here we also imposed certain initial and strong anchoring boundary conditions. It is also proved that below the threshold, the asymptotic limit is the trivial state.