A three-phase flowmeter based on a simple separator,mass flowmeter and V-core flowmeter is presented.The structure,measurement principle and measurement models are introduced.And then,some tests were carried of out under a three-phase flow experiment and calibration system.The test results of phase fraction and phase flow rate are analyzed.Finally,the performance of the three-phase flowmeter in the field is tested,and the problems exist in the meter is described.