Abstarct: One of the application of differential equations is in engineering sciences. A geometrical structure is defined on physical phenomena by a coordinate chart will be defined on the considered structure. One of the important differential equations in fluid mechanics is three dimension Kudryashov-Sinelshikov equation which is describing the pressure waves in a mixture liquid and gas bubbles taking into consideration the viscosity of liquid and the heat transfer, it is generalization of the KdV and the BKdV equation and similar but not identical to the Camassa-Holm equation. In this thesis we apply Lie theory of differential equation for finding some exact solution of the equation.