The solvation free energies of cyclic dipeptides (CDPs) for a membrane were calculated to evaluate their membrane permeabilities. As a result, there were energy barriers between the membrane center and interface for each CDP. Furthermore, the profiles of solvation free energy depended on the amino acids that construct each CDP. These results indicate that each CDP changes its membrane permeability. Our results will be useful for designing cyclic peptides in the field of medium-molecular-weight drugs.