In recent years, the forecasting of tropical cyclone (TC) intensity has been improved. However, the intensity forecasting value is weaker in the years when TCs are frequently intensified over offshore waters. Focused on the factors affecting the intensified coastal TCs, this paper reviews the related research from two perspectives: environmental conditions and dynamic mechanism. Then a detailed analysis of the effects of environmental atmospheric, ocean forcing mechanisms, structural changes in the inner core and water phase change in spiral bands on the intensifying process of coastal TCs is performed. Such factors are good indicators for the forecasting of coastal TCs, and they act together in the TC intensifying process. Through comparing and summarizing relevant research results, a schematic model of impact factors is established in order to provide valuable reference for operational forecasting of the intensifying process of TCs over offshore waters.