On the basis of the barrier method, a unified approach for the static output feedback sliding mode control of linear control systems with matched uncertainty is addressed. Without coordinate transformations, a structured static output feedback sliding surface matrix is obtained by solving a constrained minimization problem, and then a globally stabilizing static output feedback sliding mode controller can be constructed directly. The Lagrange multiplier method is used to derive the necessary conditions for the optimal solution of the minimization problem. An iterative gradient descent algorithm is established to search for a (local) optimal solution. Finally, for validation, a numerical example is proposed.