Based on the processes of droplet nucleation, growth, coalescence and departure, the heat transfer model of dropwise condensation of a pure vapour on hydrophobic/superhydrophobic surfaces is developed. The influences of the number of nucleation site, minimum radius, contact angle and departure radius on heat transfer performance are studied by numerical simulation. The results indicate that the minimum radius affects the dropwise condensation a little while it is much less than the characteristic coalescence radius. The internal droplet thermal resistance increases as the contact angle increases. As a result, the heat transfer performance of superhydrophobic surfaces is not as good as that of hydrophobic surfaces.