This paper proposes an implementation method of reference governor. If the constrained variables at the steady state are 0, it is rather easy to compute the maximal output admissible set Ω∞. However, if the constrained variables at the steady state are not 0, then computing Ω∞ is very difficult. We do not compute the Ω∞, but we propose a parametric characterization of Ω∞. By using this characterization, we propose an algorithm to decide reference signal r[k] on-line so that constraints are not violated. The usefulness of the proposing method is examined through numerical examples.