Two-phase flow (two-phase flow) is part of a multi-phase flow that only involves two forms of a substance in a flow. Two-phase flow can occur in large channels or pipes (large channel), normal (normal channel), mini (mini channel), micro (micro channel), and even on the nano channel (nano channel). In industrial processes, among others: heat exchangers, boilers, geothermal, and piping systems. This research aims to find out characteristic information about flow patterns, flow pattern maps, vacuum fractions and two-phase pressure greadient flow in mini channels. This research was conducted in the test section in the form of a glass pipe with a diameter of 1.6 mm with an angle of 20⁰ to the horizontal position. The fluid used is a mixture of air-water and 3% butanol. The superficial velocity values of water and air are varied, namely JL = 0.033 - 4.93 m / s and JG = 0.025 - 66.3 m / s. Characteristic data of flow patterns and vacuum fractions are taken using a high speed camera with a speed of 1200 FPS. In this study flow patterns are processed using visualization methods with the MOV to AVI program and then processed with virtual dub. The vacuum fraction was calculated using the digital image processing method with the MATLAB R2014a program. The pressure gradient uses the MPX System fluid pressure sensor that is connected to the computer. Based on the results of research conducted on the flow patterns obtained are: annular, bubbly, churn, plug and annular slug. The flow pattern map obtained in this study is more dominant in the plug and churn flow patterns. The value of the vacuum fraction is influenced by the varied JG and JL and the flow patterns that occur. As for the pressure gradient results show that the gas superficial velocity (JG) and liquid superficial velocity (JL) greatly affect the pressure gradient value the higher the JG and JL values, the pressure gradient value will increase. The value of surface tension and the tilt angle affect the shape of the flow pattern and the pressure gradient value.