Using the criterion of the free energy,we prove that the mechanical equilibrium condition for liquid droups on the condenser surface depends on the angle of contact (α).For α＞90°the chemical potential of liquid drops on the condenser surface is less than that of spherical drops with the same curvature.And the critical radius of the former is also less than that of the latter if they are at the same saturation level.For this reason the heat-transfer capability of liquid drops condensed on the walls of a vessel is stronger than that of the condensed liquid film.The suitable value is determined for the angle of contact.