Abstract: Flue gas of industrial coal-fired boiler contains lots of fly ash particles, viscous substances and acid gases.Among them, fly ash particles are easy to interact with other substances and form ash deposition on the heating surface of the heat exchanger, which can influence the heat transfer performance of the equipment and the stable operation of system. Therefore, the method which can decrease or even avoid the fly ash deposition is an important research topic for the practical application. There are many factors affecting the deposition of fly ash particles, such as working condition and heat exchanger structure that may lead to considerably different fly ash deposition processes on the heated surface. In order to well understand the influence factors and characteristics of ash deposition on heat transfer surface, the existed researches were reviewed and analyzed in this paper. Firstly, the formation,transportation, adhesion and growth mechanism of fly ash in boiler system were expounded. Then, the main influence factors and influence rules of the fly ash deposition were analyzed in detail and the correlation formulas of the effect of ash deposition on heat transfer performance are summarized.Finally, guidelines were provided for designing the anti-fouling and high performance heat exchanger, which can offer help to select the suitable operation conditions for reducing ash deposition. Furthermore, the shortages of existed researches on ash deposition at the heat transfer surface and the future research directions were discussed.