The fluid flow is not only the single phase but often obtained also multiphase flow. One of multiphase flow is a two-phase flow. On two-phase flow potentially forming a variety of flow pattern caused a lot of things. Therefore necessary the proper calculations to avoid bad things happen. One of the method the flow is research by the computing system or commonly known as the term Computational Fluid Dynamics (CFD). CFD is very suitable for an analysis of a complex and difficult system to solve with manual calculation. In this research to know the phenomena of flow pattern in a two-phase flow in a horizontal capillary pipe by numerical simulation using software ANSYS Fluent 19.0 academic. The simulation was carried out on the 2-dimensional horizontal capillary pipe with a diameter of 1.6 mm and a length of 100 mm. The fluid using an air-water mixture and glycerin 0%, 10%, 20%, and 30% with the variation liquid superficial velocity (JL) = 0.033 m/s – 4.935 m/s and gas superficial velocity (JG) = 9.62 m/s. The results of the simulations showed a flow pattern that emerges from all of the variations is a slug-annular flow pattern and churn flow pattern. On the slugannular flow pattern, viscosity effected on the abundance of liquid that clings to the walls of the pipe, the more viscous the liquid viscosity, resulting in more and more stuck in the pipe wall.