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 be classified based on the size of the channel, namely, large channels, normal (normal channel), mini (minni channel), micro (micro channel), nano (nano channel). This research aims to find out information about flow patterns, flow pattern maps, void fractions and two-phase pressure pressure gradients on 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 a length of 130 mm with an angle of 20⁰ to the horizontal position. The fluid used is a mixture of air-water and 5% 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. In this study flow patterns are processed using visualization methods with the MOV to AVI program and then processed with virtual dub. The void 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. In this study the results of flow patterns obtained are: annular, bubbly, churn, plug and annular slug. The results of the void fraction showed that the higher the value of the JG, the greater the value of the void fraction, while the higher the JL value, the value of the void fraction decreased. 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.