Abstract: E. L. Heric presented an improved method of compound synthesis that indicated the ternary aqua-sahs phase diagram can be constructed by determining only the aqueous content of the saturated solution in the equilibrium system. Based on Heric's principle an experimental study in constructing aqua-salts phase digrams for four basic types of NaNO_3-Pb(NO_3)_2-H_2O, NH_4Cl-BaCl_2-Ha_2WO_4-Na_2MoO_4-H_2O, Na_2SO_4-MgSO_4-H_2O system was completed, and the results showed fairly consistent with the data in literatures. It proves that Heric's method is feasible. In this paper, the experimental study is described in detail, and the reliability and applicability of Heric's method are discussed.