Abstract: The measurement of phase concentration is urgently in need due to its importance in the measurement, control and reliable operation of industrial processes. The principles, applications and research results of present measuring methods for the phase concentration of two phase flows are described in detail. Present conditions and problems existing in phase concentration measurement techniques are analyzed, and the capacitive method for phase concentration measurement is given emphasis. Design fundamentals of the capacitive transducer are given. Under a comparison and analysis of the various phase concentration measurement techniques, the advantage and broad industrial application prospect of capacitance sensors are clarified. Trends of two phase flow measuring techniques are then presented.