Abstract: Concrete specimens were coated with epoxy phenolic coatings and coal tar epoxy coatings, respectively. Hot water accelerated aging tests of the coated concrete specimens were carried out in circulating water and deionized water. In the aging process, the water absorbing capacity of these coatings was measured and the surface morphologies were observed. The dependence of water absorbing capacity on suction time and aging time was analyzed to find out a method for evaluating the service life of anticorrosion coatings on cooling towers with circulating water. It is indicated that the service life of the coatings at the test temperature can be predicted according to the inflection point on the curve of water absorbing capacity to aging time, and then the service life at the service temperature can also be calculated based on the Vant Hoff regulation.