Benjamin-Ono Equation are significantly important in describes the one-dimensional internal waves in deep water. Because of its significance, Lie symmetry reduction were chosen to reduce the equation and hence solve the equation. Lie symmetry analysis is one of the powerful methods to solve partial differential equation. Due to its effectiveness, this method is widely applied in solving equation in various field. In this paper, calculation of symmetry of the equation was first present, followed by reduction of the equation. The equation are reduced from non-linear partial differential equation (PDE) to ordinary differential equation (ODE) and hence analytic solution of the partial differential equation was obtained by solving the reduced ODE.