In this article, we investigate the nonlinear stability of the Couette flow under the Boussinesq equations with only vertical dissipation in \({\mathbb {T}}\times {\mathbb {R}}\) . Inspired by the work of Wei and Zhang [Tunis. J. Math. 5(3):573-592 (2023)] and taking into account perturbations with different sizes, we can address the influence of buoyancy term within the coupled system. We obtain a stability result under the initial perturbations condition: \(\Vert \omega ^{(0)}\Vert _{H^b}+\nu ^{-1/2}\Vert \theta ^{(0)}\Vert _{H^b}+\nu ^{-1/6}\Vert \partial _x\theta ^{(0)}\Vert _{H^b}\lesssim \nu ^{1/3}\) , where \(b\ge 2\) .
