To measure the temperature distribution of molten pool in twin-roll strip casting, a new method based on the soft measurement of temperature field and on-line measurement of fixed point temperature was presented. A threedimensional model on coupled turbulent flow and heat transfer, was firstly established. With regard of the four outlets nozzle, the numerical solution of temperature field was achieved and compared with the real time measurement in order to calibrate the model. A function library, thus, is derived and characterized by the relationship between temperature distribution and main features such as the submerged depth of delivery system, casting temperature, contacting arc, roll speed, casting angel, material properties and roll gap. By applying real time adjustment to the function library, this new method may increase the accuracy, reliability and rapidness of the measurement of molten pool temperature field.