Abstract: Gas-liquid two-phase flow metering separators based on the extracting and separating method is disadvantageous with complex structure and unstable liquid level. To deal with this situation, a new type of gas-liquid two-phase flow tube separator was designed and prepared. The effects of gas and liquid superficial velocity and inlet conditions of different flow patterns on its separation result were investigated by means of numerical simulation and then experimentally verified. And the working performance of this separator was evaluated. It is shown that in the patterns of stratified flow, slug flow and annular flow, the gas-liquid separation effect inside the separator is good and the gas-liquid interface inside the separator keeps stable and maintains in the middle of the separator. It is verified from experiments that when gas flow and liquid flow range 50-1500 L/min and 50-2400 kg/h, respectively, the gas-liquid interface inside the separator keeps stable, separation error is less than ±2.5% and metering results are good and accordant with the simulation results. This tube separator is characterized by simple structure and stable working fluid level. It provides technical support for the design of two-phase flow metering separator based on the extracting and separating method.