In order to eliminate mal-distribution and ensure the side arm to produce desirable gas quality a special distributor is proposed. The experimental distributor mainly consists of a straight through section, a gas extraction line, a liquid extraction line and a side arm branch. A gas orifice and a liquid orifice are mounted at the gas and liquid extraction line respectively to control the outlet gas quality. The diameter of the liquid orifice was set to 2?50 mm and three gas orifices with different size ( dG = 2?65, 5?00, 10?00 mm) were tested. The experiments were carried out at an air-water two-phase flow loop. The gas superficial velocity ranged from 6?0 to 20?0 m/s and the liquid superficial velocity was in the range of 0?02-0?18 m/s. Flow patterns such as wave flow, slug flow and annular flow were observed. The gas quality of the side arm branch was found mainly determined by the flow area ratio of the gas orifice to the liquid orifice and independent of gas and liquid superficial velocity, flow patterns and extraction flux.