Oscillating heat pipe is one of the emerging heat transfer technologies that have received much attention from people. The general structure of the oscillating heat pipe is a close loop consisting of a meandering capillary tube over two-dimensional plane. In this study, the performance of oscillating heat pipe with three-dimensional structure is investigated experimentally. Four glass tubes are connected to the heating and cooling aluminum plates perpendicularly. The inner diameter of glass tube is 1.2 mm. Ethanol, water and Novec(HFE-7100) are used as working fluids. Flow pattern and thermal resistance are investigated as changing heating power and filling ratio of working fluids. The thermal resistance of oscillating heat pipe decreases with increasing heating power. Oscillation in capillary tube starts earlier at smaller filling ratio, however dryout also occurs earlier. Among three working fluids, Novec shows the highest thermal performance.