Ionic models are used to describe the evolution of the electrical potential across the cardiac cell membranes. The Mitchell-Schaeffer model is a simple two variables nonlinear ionic model with a limited set of parameters. This model can still capture the main features of the cardiac action potential, namely the action potential duration (APD), the conduction velocity (CV), depolarisation time (DT), recovery time (RT), etc. In this paper we have developed an optimization method to recover the specific characteristics ADP, DT and RT by identifying the values that the four parameters τ = [τ in , τ out , τ open , τ close , σ] of the Mitchell-Schaeffer must take. By using the fonction ode in Scilab, Mitchell-Schaeffer model solutions have been oabtained numerically.