Solvation is an elementary process in nature and is of paramount importance to many sophisticated chemical, biological and biomolecular processes. The understanding of solvation is an essential prerequisite for the quantitative description and analysis of biomolecular systems. Implicit solvent models, particularly those based on the Poisson-Boltzmann (PB) equation for electrostatic analysis, are established approaches for solvation analysis. However, ad hoc solvent-solute interfaces are commonly used in the implicit solvent theory and have some severe limitations. We have introduced differential geometry based multiscale solvation models which allow the solvent-solute interface, electrostatic potential, and even electron densities to be determined by the variation of a total free energy functional. Our models are utilized to evaluate the solvation free energies, protein-protein binding, ion channel charge transport etc.