The paper describes the sensor and methodology to measure the void fraction and flow rate of liquefied natural gas two-phase flow. The design and calibration procedure of high frequency sensors as well as sensitivity and accuracy are discussed. High frequency method is used for void fraction measurements. Flow rate is measured by cross-correlation technique. The automatic measuring system to control two-phase cryogenic flows is described. Application of the system for testing fuel pumps of aircraft using cryogens as propellants is demonstrated. Results of calibration of the system on liquefied natural gas flow are presented