The application of two phase-flow is very wide with the rapid of development of science and technology on industry, electronics until atutomotive causing humans to create increasingly compact and practical tools. To support this, i tis necessary to adjust the two-phase flow system using a minichannel. Different from konventional channel, minichannels are not affected by gravity but influenced by surface tension. In the author’s opinion that several studies of surface tension have not yet revealed the effect of surface tension on the characteristic of two-phase flow in minichannels. The test section was 1.6 mm with incline angle 10° to horizontal orientation. The working fluids used in this research were aquades and 3% butanol with 42.90 mN/m surface tension. Variation of gas and liquid superfisial velocities were 0 m/s – 66,3 m/s and 0,033 m/s – 4,935 m/s. Flow pattern and void fraction data obtained from video images which recorded with a high-speed camera. Pressure gradient obtained from data processing from data acquisition. As a result, there were five flow pattern that have been found in this present study: bubbly, plug, slug-annular, annular and churn. Flow pattern map showed suitability with Triplett et al. (1999) and Chung and Kawaji (2004) research. Surface tension affected shape of bubbly and plug flow pattern. Increasing the value of JG cause the value of void fraction to increase as well. Increased superfisial velocities of both gas and liquid affects the increase of pressure gradient