Abstract: A method and device for a liquid media parameters determination, wherein an extended heater oriented along the fluid flow is installed in the fluid flow. Fluid flow temperature is measured. The heater is heated up and the temperatures at the interfaces “heater front surface?flow zone” and “heater rear surface?flow zone” are measured; for the both interfaces, measured values are used for calculating temperature difference between the said heater and the flow, while the water-to-oil relationship is determined through calculations by using either mathematical or graphic relationships. The device for determining the parameters of fluid flow comprising a heater, characterized in that the heater has an extended shape and is oriented along the fluid flow direction, with two thermal sensors located at the opposite ends of the heater, which are capable of transmitting measured data remotely.