In this paper we use the global extrapolation procedure to study the Boussinesq equation in one dimension. The application of a parametric finite-difference method leads to a three-time level nonlinear scheme, which is analyzed for local truncation error, stability and convergence, Then, the nonlinear term of the equation is properly linearized so, that the scheme becomes linear. The results of a number of numerical experiments for the single-soliton wave are given.