We present a novel empirical tight-binding model of the hydrogen-silicon system suitable for realistic molecular-dynamics simulations. The hydrogen-silicon and hydrogen-hydrogen interactions are constructed to reproduce the electronic levels and vibrational frequencies of silane (SiH₄) and hydrogen molecules, respectively. The potential functions are rescaled with an exponential factor in addition to the simple inverse square law. This smooths the potential change at some appropriate cut-off distances, which is a prerequisite condition in realistic molecular-dynamics simulations. The application of this model to other molecules and surfaces yields excellent agreement with the experimental results, proving the good transferability of our model.