An experimental flow loop was designed and constructed to perform the wax deposition tests under the oil/gas two-phase flow conditions in a horizontal pipe. The oil sample came from the Daqing Oilfield of China, which was characterized by high wax content. A particular local sampler was designed and installed at the outlet of the test section in the flow loop to make up for the drawback of no visual observation during the course of flow pattern verification; which is a good device to help verify the flow pattern by analyzing the inner flow situations at different circumferential and vertical positions. Using the local sampler in combination with analyzing the changes in pressure drop and liquid holdup, which is defined as the fraction of an element of pipe occupied by liquid at the same instant, flow patterns were identified and divided into two main categories, namely, the stratified flow and slug flow. Wax deposition tests were selected in the definite flow pattern regions instead of flow pattern transition regions. The effects of flow pattern Characteristics on wax deposition were experimentally studied under the oil/gas two-phase flow conditions. The results show,. that liquid superficial velocity, gas superficial velocity, shear stress at the liquid-deposit interface, liquid holdup, and slug frequency do play an important role in wax deposition the oil/gas two-phase flow. The wax deposition characteristics were experimentally obtained for stratified flow and slug flow. The experimental results in this study provide an experimental reference and insight for study on wax deposition in multiphase flow, especially under the conditions that the oil sample is characterized by high wax content.