A new DDLC (density dependent local composition) model which possesses sound theoretical background describing both size and energy asymmetries of molecules has been developed. Dividing the radial distribution function into packing and attractive effects new local composition model naturally satisfies high and low density boundary conditions and it shows desirable characteristics to represent computer simulated local composition data correctly. Based on the new local composition model, DDLC mixing rule for the cubic equation of state has been derived and utilized to calculate the solubilities of solids in supercritical fluid mixtures. It has been found that new version of DDLC mixing rule shows excellent capabilities to predict solubilities of solids in various supercritical fluid systems including solid mixtures or entrainers.