Simulation of linear and non-linear waves in numerical wave tank has been one of the most important topics of interest to researchers and scholars working in the areas of the marine industries. In this paper, due to capabilities of the boundary element method, nonlinear waves generated by a piston type wave-maker in a 2D wave tank was investigated. For time evolving of wave in the simulation and solving the free surface boundary conditions equations, the conventional Euler-Lagrangian method was used. For evaluation of results, a sample wave was chosen for simulation and its result was compared with a result of an analytical method. Finally, the results from the simulation of piston wave-maker was presented. Then, the process of calibrating a sample wave-maker was described for a desired range.