In this work, we investigate the limit behavior as → 0 for the solutions of the Cauchy problem of the Sixth-order Boussinesq equationWe show that its local solution converges to that of the Boussinesq equation, s ≥ 0, as tends to 0. The ill-posedness result of Esfahani and Farah (J. Math. Anal. Appl. 385:230-242, 2012) will be here improved by proving that the associated flow map is not smooth for s < −1.