Using the ESTPHAD (Estimation of Phase Diagrams) method, the liquidus and solidus curves in the equilibrium phase diagram can be created by thermodynamic based equations. By these determined equations, the liquidus or solidus temperatures as a function of concentration can be calculated with the required precision. The main advantages of the ESTPHAD method are as follows: the parameters of functions can be calculated simply, it gives a precise result and the calculation time is short. This paper shows the reconstruction of the liquidus curves of the CaO-Al2O3 phase diagram (0-60 wt% Al2O3 range) by using the ESTPHAD method on the basis of the measured data. The divergences between the measured and calculated (ESTPHAD) data are less than the given measurement error (±10 K).