The Na,K,Ca,Ba‖F,WO4 quinary mutual system was differentiated based on graph theory with consideration of identified internal secant elements using a program complex. For the first time, by a combination of physicochemical analysis methods (differential thermal, visual polythermal, X-ray diffraction and projection-thermal-analytical), the NaF-K2WO4-CaF2-BaF2 quaternary system was studied, which is a stable secant complex of the quinary mutual system. The coordinates of invariant points were determined.