Two-phase flow is used in many industries such as in a nuclear reactor, boiler, condenser, liquefaction of natural gas and etc. Two-phase flow is a stream which flows in a pipe having two fluid such as liquid-solid, solid–gas, gas-solid. There is a two-phase flow in the three channels, namely vertical, horizontal, and oblique. On the horizontal flow pattern that is found is a flow pattern of stratified flow, bubble, plug flow, stratified wavy flow, annular flow and slug flow. Keywords : Two-phase flow, flow patterns, CFD, pressure gradient. This research was conducted to find the flow pattern and pressure gradient using software Computational Fluid Dynamics (CFD) Ansys Fluent 19.0 Student. The model used the Volume Of Fluid (VOF) with the working fluid is air-water and Glycerin (40%-70%). The length of the pipe 200 mm, inside diameter 1,6 mm and a length of 100 mm. Superficial water speed (JL) used is 0,033 m/s; 0,149 m/s; 0,232 m/s; 0,539 m/s; 0,7 m/s; 2,297 m/s and 4,935 m/s, while superficial velocity of air (JG) was 9,62 m/s. The result of the simulation is the flow pattern of slug annular and churn. Slug annular formed at JL= 0,033 m/s; 0,149 m/s and 0,232 m/s with a percentage of 40% glycerine and glycerin 50%, 60% and 70% with JL= 0,539 m/s flow pattern formed slug annular. The viscosity effect on the pattern of the flow, the higher the percentage of glycerine then viscosity will be even greater and more fluid than on the air. The higher the JL and percentage of glycerin result pressure gradient will be even greater.