Abstract: An equation of state(EOS) for square-well chain fluid with variable range(SWCF-VR) was simplified according to the characteristics of molten metals. If the metal is considered as a sphere, the simplified EOS contains three parameters, including hard sphere diameter, molecule interaction energy and reduced well width. Among them, the hard sphere diameter can be replaced by the metal atomic diameter, and the square-well depth and width can be obtained by the regression of experimental data of density of 16 different molten metals. This proposed two-parameter EOS was employed to the density calculation of alkali metals, alkaline earth metals, transient metals and their alloys. The results show that EOS can satisfactorily predict the density of 16 liquid metals in a wide range of temperatures as well as at a high pressure with a overall average deviation of 0.16%. Furthermore, EOS can satisfactorily predict the density of alloys at various temperatures, pressures and components using the binary interaction adjustable parameter independent of temperature.