It is well known that the wet compression technique is effective to improve the performance of gas turbines. A thorough understanding of the droplet behavior within compressor is important to achieve full potentials of the wet compression. A model has been developed to investigate the evaporation time of a water droplet. The temperature of a water droplet has been calculated by treating the droplet as a lumped thermal mass with one representative temperature uniformly distributed in the droplet. It is assumed that the change of the water droplet temperature is caused by convective heat transfer through the droplet surface. Then the evaporation time of a water droplet has been calculated based on either evaporation or boiling conditions.